basectx: move __getitem__ from changectx

mercurial/context.py

@@ -56,6 +56,9 b' class basectx(object):'
     def __contains__(self, key):
         return key in self._manifest
 
+    def __getitem__(self, key):
+        return self.filectx(key)
+
     @propertycache
     def substate(self):
         return subrepo.state(self, self._repo.ui)
@@ -200,9 +203,6 b' class changectx(basectx):'
             p = p[:-1]
         return [changectx(self._repo, x) for x in p]
 
-    def __getitem__(self, key):
-        return self.filectx(key)
-
     def __iter__(self):
         for f in sorted(self._manifest):
             yield f