help: allow -k to find debug commands

mercurial/help.py

@@ -92,8 +92,6 b' def topicmatch(kw):'
             results['topics'].append((names[0], header))
     import commands # avoid cycle
     for cmd, entry in commands.table.iteritems():
-        if cmd.startswith('debug'):
-            continue
         if len(entry) == 3:
             summary = entry[2]
         else: