Add some qualifications on the info

Author: tbrowder

doc/Language/regexes.pod6

@@ -1612,7 +1612,7 @@ backslash C<\> or included in quotes:
 
 Note that the matching restrictions generally only apply to the left-hand side of the
 substitution expression, but some special characters or combinations of them may need
-to be escaped. For example
+to be escaped in the right-hand side (RHS). For example
 
     $_ = 'foo';
     s/foo/\%(/;
@@ -1624,7 +1624,9 @@ or escape the '(' instead for the same result
     .say        # OUTPUT: «%(␤»
 
 but using either character alone does not require escaping. Forward slashes will need
-to be escaped, but escaping alphanumeric characters will cause them to be ignored.
+to be escaped, but escaping alphanumeric characters will cause them to be ignored. (NOTE:
+This RHS limitation was only recently noticed and this is not yet an exhaustive list of all characters
+or character pairs that require escapes for the RHS.)
 
 By default, substitutions are only done on the first match: