Remove docs for non-existent feature.

Closes #1093

doc/Language/regexes.pod6

@@ -303,13 +303,13 @@ with two dots between the end points), with or without whitespace.
     # Unicode named codepoint range
     "ÀÁÂÃÄÅÆ" ~~ / <[ \c[LATIN CAPITAL LETTER A WITH GRAVE] .. \c[LATIN CAPITAL LETTER AE] ]> /
 
-Between the C<< < > >> you can also use the same operators for categories
-(C<+>, C<|>, C<&>, C<->, C<^>) to combine multiple range definitions and
+Between the C<< < > >> you can also use C<+> and C<-> to add or
+remove multiple range definitions and
 even mix in some of the unicode categories above. You are also allowed to
 write the backslashed forms for character classes between the C< [ ] >.
 
     / <[\d] - [13579]> /
-    # not quite the same as
+    # starts with \d and removes odd ASCII digits, but not quite the same as
     / <[02468]> /
     # because the first one also contains "weird" unicodey digits