regexp/syntax: add note about Unicode character classes

As proposed on golang-nuts:
https://groups.google.com/g/golang-nuts/c/M3lmSUptExQ/m/hRySV9GsCAAJ

Includes the latest updates from re2's mksyntaxgo:
https://code.googlesource.com/re2/+/refs/heads/master/doc/mksyntaxgo

Change-Id: Ib7b79aa6531f473feabd0a7f1d263cd65c4388e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/264678
Reviewed-by: Russ Cox <rsc@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>

diff --git a/src/regexp/syntax/doc.go b/src/regexp/syntax/doc.go
index efc0b435711f3cfd1f50cc5d6d21090c5b5a7588..b3f9136b5f3194b1594977a3078a51eb214adb45 100644 (file)
--- a/src/regexp/syntax/doc.go
+++ b/src/regexp/syntax/doc.go
@@ -66,7 +66,7 @@ Grouping:
 
 Empty strings:
   ^              at beginning of text or line (flag m=true)
-  $              at end of text (like \z not Perl's \Z) or line (flag m=true)
+  $              at end of text (like \z not \Z) or line (flag m=true)
   \A             at beginning of text
   \b             at ASCII word boundary (\w on one side and \W, \A, or \z on the other)
   \B             not at ASCII word boundary
@@ -127,5 +127,6 @@ ASCII character classes:
   [[:word:]]     word characters (== [0-9A-Za-z_])
   [[:xdigit:]]   hex digit (== [0-9A-Fa-f])
 
+Unicode character classes are those in unicode.Categories and unicode.Scripts.
 */
 package syntax