io.c: fix rdoc of append mode

* io.c (rb_io_initialize): [DOC] fix rdoc of append mode.  it does
  not move the pointer at open.  [ruby-core:63747] [Bug #10039]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46876 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sun Jul 20 00:32:44 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (rb_io_initialize): [DOC] fix rdoc of append mode.  it does
+	  not move the pointer at open.  [ruby-core:63747] [Bug #10039]
+
 Sat Jul 19 12:40:50 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* compile.c (iseq_compile_each): allow to access private attribute

io.c

@@ -7390,12 +7390,12 @@ rb_io_stdio_file(rb_io_t *fptr)
  *  	"w+" Read-write, truncates existing file to zero length
  *  	     or creates a new file for reading and writing.
  *
- *  	"a"  Write-only, starts at end of file if file exists,
- *  	     otherwise creates a new file for writing.
+ *  	"a"  Write-only, each write call appends data at end of file.
+ *  	     Creates a new file for writing if file does not exist.
  *
- *  	"a+" Read-write, starts at end of file if file exists,
- *	     otherwise creates a new file for reading and
- *  	     writing.
+ *  	"a+" Read-write, each write call appends data at end of file.
+ *	     Creates a new file for reading and writing if file does
+ *	     not exist.
  *
  *  The following modes must be used separately, and along with one or more of
  *  the modes seen above.