Add obsolescence note to the module descriptions that get added to the

list of module synopses at the front of the chapter; based on a comment
from Aahz <aahz@panix.com>.

Doc/lib/libregex.tex

@@ -1,8 +1,9 @@
 \section{\module{regex} ---
-         Regular expression search and match operations.}
+         Regular expression operations}
 \declaremodule{builtin}{regex}
 
-\modulesynopsis{Regular expression search and match operations.}
+\modulesynopsis{Regular expression search and match operations.
+                \strong{Obsolete!}}
 
 
 This module provides regular expression matching operations similar to