Fixed mistake in docs

regex/doc.go

@@ -33,7 +33,7 @@ Perl classes:
 	\d				Match any digit character ([0-9])
 	\D				Match any non-digit character ([^0-9])
 	\w				Match any word character ([a-zA-Z0-9_])
-	\W				Match any word character ([^a-zA-Z0-9_])
+	\W				Match any non-word character ([^a-zA-Z0-9_])
 	\s				Match any whitespace character ([ \t\n])
 	\S				Match any non-whitespace character ([^ \t\n])