[DOC] Fix doc/regexp.rdoc links

- Rename regexp.rdoc to exclude from "Pages".  This file is for to be
  included in the "class Regexp" document, but it also appeared as a
  separate page duplicately.
- Fix links on case-sensitive filesystems.
- Fix to use rdoc-ref instead of converted HTML page names.

dir.rb

@@ -320,7 +320,7 @@ class Dir
   #     Dir.glob('io.?') # => ["io.c"]
   #
   # - <tt>'[_set_]'</tt>: Matches any one character in the string _set_;
-  #   behaves like a {Regexp character class}[rdoc-ref:regexp.rdoc@Character+Classes],
+  #   behaves like a {Regexp character class}[rdoc-ref:Regexp@Character+Classes],
   #   including set negation (<tt>'[^a-z]'</tt>):
   #
   #     Dir.glob('*.[a-z][a-z]').take(3)
@@ -328,7 +328,7 @@ class Dir
   #
   # - <tt>'{_abc_,_xyz_}'</tt>:
   #   Matches either string _abc_ or string _xyz_;
-  #   behaves like {Regexp alternation}[rdoc-ref:regexp.rdoc@Alternation]:
+  #   behaves like {Regexp alternation}[rdoc-ref:Regexp@Alternation]:
   #
   #     Dir.glob('{LEGAL,BSDL}') # => ["LEGAL", "BSDL"]
   #

doc/.document

@@ -1,6 +1,6 @@
 *.md
 *.rb
-*.rdoc
+[^_]*.rdoc
 contributing
 NEWS
 syntax

doc/_regexp.rdoc

@@ -25,46 +25,46 @@ A regexp may be used:
     re.match('food')        # => #<MatchData "foo">
     re.match('good')        # => nil
 
-  See sections {Method match}[rdoc-ref:regexp.rdoc@Method+match]
-  and {Operator =~}[rdoc-ref:regexp.rdoc@Operator+-3D~].
+  See sections {Method match}[rdoc-ref:Regexp@Method+match]
+  and {Operator =~}[rdoc-ref:Regexp@Operator+-3D~].
 
 - To determine whether a string matches a given pattern:
 
     re.match?('food') # => true
     re.match?('good') # => false
 
-  See section {Method match?}[rdoc-ref:regexp.rdoc@Method+match-3F].
+  See section {Method match?}[rdoc-ref:Regexp@Method+match-3F].
 
 - As an argument for calls to certain methods in other classes and modules;
   most such methods accept an argument that may be either a string
   or the (much more powerful) regexp.
 
-  See {Regexp Methods}[./Regexp/methods_rdoc.html].
+  See {Regexp Methods}[rdoc-ref:regexp/methods.rdoc].
 
 == \Regexp Objects
 
 A regexp object has:
 
-- A source; see {Sources}[rdoc-ref:regexp.rdoc@Sources].
+- A source; see {Sources}[rdoc-ref:Regexp@Sources].
 
-- Several modes; see {Modes}[rdoc-ref:regexp.rdoc@Modes].
+- Several modes; see {Modes}[rdoc-ref:Regexp@Modes].
 
-- A timeout; see {Timeouts}[rdoc-ref:regexp.rdoc@Timeouts].
+- A timeout; see {Timeouts}[rdoc-ref:Regexp@Timeouts].
 
-- An encoding; see {Encodings}[rdoc-ref:regexp.rdoc@Encodings].
+- An encoding; see {Encodings}[rdoc-ref:Regexp@Encodings].
 
 == Creating a \Regexp
 
 A regular expression may be created with:
 
 - A regexp literal using slash characters
-  (see {Regexp Literals}[https://docs.ruby-lang.org/en/master/syntax/literals_rdoc.html#label-Regexp+Literals]):
+  (see {Regexp Literals}[rdoc-ref:syntax/literals.rdoc@Regexp+Literals]):
 
     # This is a very common usage.
     /foo/ # => /foo/
 
 - A <tt>%r</tt> regexp literal
-  (see {%r: Regexp Literals}[https://docs.ruby-lang.org/en/master/syntax/literals_rdoc.html#label-25r-3A+Regexp+Literals]):
+  (see {%r: Regexp Literals}[rdoc-ref:syntax/literals.rdoc@25r-3A+Regexp+Literals]):
 
     # Same delimiter character at beginning and end;
     # useful for avoiding escaping characters
@@ -84,7 +84,7 @@ A regular expression may be created with:
 
 Each of the methods Regexp#match, String#match, and Symbol#match
 returns a MatchData object if a match was found, +nil+ otherwise;
-each also sets {global variables}[rdoc-ref:regexp.rdoc@Global+Variables]:
+each also sets {global variables}[rdoc-ref:Regexp@Global+Variables]:
 
   'food'.match(/foo/) # => #<MatchData "foo">
   'food'.match(/bar/) # => nil
@@ -93,7 +93,7 @@ each also sets {global variables}[rdoc-ref:regexp.rdoc@Global+Variables]:
 
 Each of the operators Regexp#=~, String#=~, and Symbol#=~
 returns an integer offset if a match was found, +nil+ otherwise;
-each also sets {global variables}[rdoc-ref:regexp.rdoc@Global+Variables]:
+each also sets {global variables}[rdoc-ref:Regexp@Global+Variables]:
 
   /bar/ =~ 'foo bar' # => 4
   'foo bar' =~ /bar/ # => 4
@@ -103,7 +103,7 @@ each also sets {global variables}[rdoc-ref:regexp.rdoc@Global+Variables]:
 
 Each of the methods Regexp#match?, String#match?, and Symbol#match?
 returns +true+ if a match was found, +false+ otherwise;
-none sets {global variables}[rdoc-ref:regexp.rdoc@Global+Variables]:
+none sets {global variables}[rdoc-ref:Regexp@Global+Variables]:
 
   'food'.match?(/foo/) # => true
   'food'.match?(/bar/) # => false
@@ -112,8 +112,8 @@ none sets {global variables}[rdoc-ref:regexp.rdoc@Global+Variables]:
 
 Certain regexp-oriented methods assign values to global variables:
 
-- <tt>#match</tt>: see {Method match}[rdoc-ref:regexp.rdoc@Method+match].
-- <tt>#=~</tt>: see {Operator =~}[rdoc-ref:regexp.rdoc@Operator+-3D~].
+- <tt>#match</tt>: see {Method match}[rdoc-ref:Regexp@Method+match].
+- <tt>#=~</tt>: see {Operator =~}[rdoc-ref:Regexp@Operator+-3D~].
 
 The affected global variables are:
 
@@ -172,17 +172,17 @@ As seen above, the simplest regexp uses a literal expression as its source:
 A rich collection of available _subexpressions_
 gives the regexp great power and flexibility:
 
-- {Special characters}[rdoc-ref:regexp.rdoc@Special+Characters]
-- {Source literals}[rdoc-ref:regexp.rdoc@Source+Literals]
-- {Character classes}[rdoc-ref:regexp.rdoc@Character+Classes]
-- {Shorthand character classes}[rdoc-ref:regexp.rdoc@Shorthand+Character+Classes]
-- {Anchors}[rdoc-ref:regexp.rdoc@Anchors]
-- {Alternation}[rdoc-ref:regexp.rdoc@Alternation]
-- {Quantifiers}[rdoc-ref:regexp.rdoc@Quantifiers]
-- {Groups and captures}[rdoc-ref:regexp.rdoc@Groups+and+Captures]
-- {Unicode}[rdoc-ref:regexp.rdoc@Unicode]
-- {POSIX Bracket Expressions}[rdoc-ref:regexp.rdoc@POSIX+Bracket+Expressions]
-- {Comments}[rdoc-ref:regexp.rdoc@Comments]
+- {Special characters}[rdoc-ref:Regexp@Special+Characters]
+- {Source literals}[rdoc-ref:Regexp@Source+Literals]
+- {Character classes}[rdoc-ref:Regexp@Character+Classes]
+- {Shorthand character classes}[rdoc-ref:Regexp@Shorthand+Character+Classes]
+- {Anchors}[rdoc-ref:Regexp@Anchors]
+- {Alternation}[rdoc-ref:Regexp@Alternation]
+- {Quantifiers}[rdoc-ref:Regexp@Quantifiers]
+- {Groups and captures}[rdoc-ref:Regexp@Groups+and+Captures]
+- {Unicode}[rdoc-ref:Regexp@Unicode]
+- {POSIX Bracket Expressions}[rdoc-ref:Regexp@POSIX+Bracket+Expressions]
+- {Comments}[rdoc-ref:Regexp@Comments]
 
 === Special Characters
 
@@ -222,7 +222,7 @@ In particular, a source literal may contain interpolated expressions:
   /#{2 + 2}/        # => /4/
 
 There are differences between an ordinary string literal and a source literal;
-see {Shorthand Character Classes}[rdoc-ref:regexp.rdoc@Shorthand+Character+Classes].
+see {Shorthand Character Classes}[rdoc-ref:Regexp@Shorthand+Character+Classes].
 
 - <tt>\s</tt> in an ordinary string literal is equivalent to a space character;
   in a source literal, it's shorthand for matching a whitespace character.
@@ -279,7 +279,7 @@ for a character class:
     /./.match("\n")  # => nil
 
 - <tt>/./m</tt>: Matches any character, including a newline;
-  see {Multiline Mode}[rdoc-ref:regexp.rdoc@Multiline+Mode}:
+  see {Multiline Mode}[rdoc-ref:Regexp@Multiline+Mode]:
 
     /./m.match("\n") # => #<MatchData "\n">
 
@@ -578,8 +578,7 @@ called _captures_:
 The first capture is the entire matched string;
 the other captures are the matched substrings from the groups.
 
-A group may have a
-{quantifier}[rdoc-ref:regexp.rdoc@Quantifiers]:
+A group may have a {quantifier}[rdoc-ref:Regexp@Quantifiers]:
 
   re = /July 4(th)?/
   re.match('July 4')   # => #<MatchData "July 4" 1:nil>
@@ -815,7 +814,7 @@ Or by using <tt>\P</tt> (uppercase +P+):
   /\P{Alpha}/.match('1') # => #<MatchData "1">
   /\P{Alpha}/.match('a') # => nil
 
-See {Unicode Properties}[./Regexp/unicode_properties_rdoc.html]
+See {Unicode Properties}[rdoc-ref:regexp/unicode_properties.rdoc]
 for regexps based on the numerous properties.
 
 Some commonly-used properties correspond to POSIX bracket expressions:
@@ -1012,20 +1011,20 @@ arbitrary text ignored by the regexp engine:
 
 The comment may not include an unescaped terminator character.
 
-See also {Extended Mode}[rdoc-ref:regexp.rdoc@Extended+Mode].
+See also {Extended Mode}[rdoc-ref:Regexp@Extended+Mode].
 
 == Modes
 
 Each of these modifiers sets a mode for the regexp:
 
 - +i+: <tt>/_pattern_/i</tt> sets
-  {Case-Insensitive Mode}[rdoc-ref:regexp.rdoc@Case-Insensitive+Mode].
+  {Case-Insensitive Mode}[rdoc-ref:Regexp@Case-Insensitive+Mode].
 - +m+: <tt>/_pattern_/m</tt> sets
-  {Multiline Mode}[rdoc-ref:regexp.rdoc@Multiline+Mode].
+  {Multiline Mode}[rdoc-ref:Regexp@Multiline+Mode].
 - +x+: <tt>/_pattern_/x</tt> sets
-  {Extended Mode}[rdoc-ref:regexp.rdoc@Extended+Mode].
+  {Extended Mode}[rdoc-ref:Regexp@Extended+Mode].
 - +o+: <tt>/_pattern_/o</tt> sets
-  {Interpolation Mode}[rdoc-ref:regexp.rdoc@Interpolation+Mode].
+  {Interpolation Mode}[rdoc-ref:Regexp@Interpolation+Mode].
 
 Any, all, or none of these may be applied.
 

re.c

@@ -538,7 +538,7 @@ static VALUE rb_reg_str_with_term(VALUE re, int term);
  *
  *  The returned string may be used as an argument to Regexp.new,
  *  or as interpolated text for a
- *  {Regexp interpolation}[rdoc-ref:regexp.rdoc@Interpolation+Mode]:
+ *  {Regexp interpolation}[rdoc-ref:Regexp@Interpolation+Mode]:
  *
  *    r1 = Regexp.new(s0) # => /(?ix-m:ab+c)/
  *    r2 = /#{s0}/        # => /(?ix-m:ab+c)/
@@ -4692,7 +4692,7 @@ rb_reg_timeout_get(VALUE re)
 /*
  *  Document-class: Regexp
  *
- *  :include: doc/regexp.rdoc
+ *  :include: doc/_regexp.rdoc
  */
 
 void

string.rb

@@ -76,7 +76,7 @@
 #  - <tt>\n</tt> (_n_ a non-negative integer) refers to <tt>$n</tt>.
 #  - <tt>\k<name></tt> refers to the named capture +name+.
 #
-#  See rdoc-ref:regexp.rdoc for details.
+#  See Regexp for details.
 #
 #  Note that within the string +replacement+, a character combination
 #  such as <tt>$&</tt> is treated as ordinary text, and not as
@@ -93,7 +93,7 @@
 #  - <tt>\\+</tt> corresponds to <tt>$+</tt>,
 #    which contains last capture group.
 #
-#  See rdoc-ref:regexp.rdoc for details.
+#  See Regexp for details.
 #
 #  Note that <tt>\\\\</tt> is interpreted as an escape, i.e., a single backslash.
 #