Fix a stub docs issue

jedi/inference/names.py

@@ -341,6 +341,12 @@ class TreeNameDefinition(AbstractTreeName):
     def py__doc__(self):
         api_type = self.api_type
         if api_type in ('function', 'class', 'property'):
+            if self.parent_context.get_root_context().is_stub():
+                from jedi.inference.gradual.conversion import convert_names
+                names = convert_names([self], prefer_stub_to_compiled=False)
+                if self not in names:
+                    return _merge_name_docs(names)
+
             # Make sure the names are not TreeNameDefinitions anymore.
             return clean_scope_docstring(self.tree_name.get_definition())
 

test/test_api/test_documentation.py

@@ -37,6 +37,17 @@ def test_operator_doc(Script):
     assert len(d.docstring()) > 100
 
 
+@pytest.mark.parametrize(
+    'code, help_part', [
+        ('str', 'Create a new string object'),
+        ('str.strip', 'Return a copy of the string'),
+    ]
+)
+def test_stdlib_doc(Script, code, help_part):
+    h, = Script(code).help()
+    assert help_part in h.docstring(raw=True)
+
+
 def test_lambda(Script):
     d, = Script('lambda x: x').help(column=0)
     assert d.type == 'keyword'