extensions.load: return module

Makes extensions.load return the module that
it has loaded.

This is done so that callers can get information on this module, which
e.g. can be used for generating docs.

mercurial/extensions.py

@@ -46,7 +46,7 b' def load(ui, name, path):'
     else:
         shortname = name
     if shortname in _extensions:
-        return
+        return _extensions[shortname]
     _extensions[shortname] = None
     if path:
         # the module will be loaded in sys.modules
@@ -66,6 +66,7 b' def load(ui, name, path):'
             mod = importh(name)
     _extensions[shortname] = mod
     _order.append(shortname)
+    return mod
 
 def loadall(ui):
     result = ui.configitems("extensions")