gendoc: restore use of callable() since it was readded in Python 3.2

doc/gendoc.py

@@ -14,7 +14,6 b' from mercurial.commands import table, gl'
 from mercurial.i18n import gettext, _
 from mercurial.help import helptable, loaddoc
 from mercurial import extensions
-from mercurial import util
 
 def get_desc(docstr):
     if not docstr:
@@ -137,7 +136,7 b' def helpprinter(ui, helptable, sectionfu'
         ui.write("\n")
         if sectionfunc:
             ui.write(sectionfunc(sec))
-        if util.safehasattr(doc, '__call__'):
+        if callable(doc):
             doc = doc()
         ui.write(doc)
         ui.write("\n")