commitablectx: move __contains__ from workingctx

mercurial/context.py

@@ -862,6 +862,9 b' class commitablectx(basectx):'
     def __nonzero__(self):
         return True
 
+    def __contains__(self, key):
+        return self._repo.dirstate[key] not in "?r"
+
 class workingctx(commitablectx):
     """A workingctx object makes access to data related to
     the current working directory convenient.
@@ -875,9 +878,6 b' class workingctx(commitablectx):'
                  changes=None):
         super(workingctx, self).__init__(repo, text, user, date, extra, changes)
 
-    def __contains__(self, key):
-        return self._repo.dirstate[key] not in "?r"
-
     def _buildflagfunc(self):
         # Create a fallback function for getting file flags when the
         # filesystem doesn't support them