Fix docstrings for wrapped functions, fixes #906

jedi/evaluate/context/decorator.py

@@ -0,0 +1,15 @@
+'''
+Decorators are not really contexts, however we need some wrappers to improve
+docstrings and other things around decorators.
+'''
+
+from jedi.evaluate.base_context import ContextWrapper
+
+
+class Decoratee(ContextWrapper):
+    def __init__(self, wrapped_context, original_context):
+        self._wrapped_context = wrapped_context
+        self._original_context = original_context
+
+    def py__doc__(self):
+        return self._original_context.py__doc__()