<?[]> and <![]> were undocumented

Author: cognominal

S05-regex.pod

@@ -1746,6 +1746,15 @@ any C<-> that would be misparsed as an identifier extender.
 
 =item *
 
+One can use character classes as assertions. The following two expressions
+are equivalent and match a variable that does not start with a sigil assuming
+that C<< <variable> >> can also match a sigil less variable.
+
+   <?[$@%&]> <variable>
+   <?before <[$@%&]> > <variable>
+
+=item *
+
 Unicode properties are indicated by use of pair notation in place of a normal
 rule name: