[DOC] `\0` is interpreted as NUL only if not followed by an octal digit.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51877 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

doc/syntax/literals.rdoc

@@ -87,7 +87,7 @@ Double-quote strings allow escaped characters such as <tt>\n</tt> for
 newline, <tt>\t</tt> for tab, etc.  The full list of supported escape
 sequences are as follows:
 
-  \0             null, ASCII 00h (NUL)
+  \0             null, ASCII 00h (NUL), only if not followed by an octal digit ([0-7])
   \a             bell, ASCII 07h (BEL)
   \b             backspace, ASCII 08h (BS)
   \t             horizontal tab, ASCII 09h (TAB)