Better annotation signature string for classes

jedi/evaluate/signature.py

@@ -39,6 +39,10 @@ class TreeSignature(AbstractSignature):
 
     @property
     def annotation(self):
+        # Classes don't need annotations, even if __init__ has one. They always
+        # return themselves.
+        if self.context.is_class():
+            return None
         return self._function_context.tree_node.annotation