Use ? instead of ?! for negated assertions, mdinger++

Author: moritz

lib/Language/regexes.pod

@@ -956,12 +956,12 @@ However, if you want to search for a pattern which is B<not> immediately
 followed by some pattern, then you need to use a negative lookahead
 assertion, this has the form:
 
-    <?!before pattern>
+    <!before pattern>
 
 Hence all occurrences of C<foo> which I<is not> before C<bar> would
 be matched by
 
-    rx{ foo <?!before bar> }
+    rx{ foo <!before bar> }
 
 =head2 Lookbehind assertions