py3: hggettext

`itervalues()` is only available on Python 2. Since this script
doesn't currently refer to the main Mercurial modules, and as a result
doesn't have easy access to the `pycompat` module, I simply changed it
to use `value()` instead. Although this allocates a list on Python 2,
I'd consider that acceptable for a utility script; Mercurial doesn't
have all _that_ many commands anyway.

Differential Revision: https://phab.mercurial-scm.org/D9259

i18n/hggettext

@@ -123,7 +123,7 b' def docstrings(path):'
     if not cmdtable:
         # Maybe we are processing mercurial.commands?
         cmdtable = getattr(mod, 'table', {})
-    functions.extend((c[0], False) for c in cmdtable.itervalues())
+    functions.extend((c[0], False) for c in cmdtable.values())
 
     for func, rstrip in functions:
         if func.__doc__: