REF: Use pdoc.Doc.source where available

Author: kernc

pdoc/__init__.py

@@ -253,7 +253,7 @@ def _pep224_docstrings(doc_obj: Union['Module', 'Class'], *,
         tree = _init_tree
     else:
         try:
-            tree = ast.parse(inspect.getsource(doc_obj.obj))
+            tree = ast.parse(doc_obj.source or None)  # type: ignore
         except (OSError, TypeError, SyntaxError) as exc:
             warn("Couldn't read PEP-224 variable docstrings from {!r}: {}".format(doc_obj, exc))
             return {}, {}

pdoc/test/__init__.py

@@ -510,8 +510,7 @@ class C:
             vars_dont = 0
             but_clss_have_doc = int
 
-        with self.assertWarns(UserWarning):
-            doc = pdoc.Class('C', pdoc.Module('pdoc'), C)
+        doc = pdoc.Class('C', pdoc.Module('pdoc'), C)
         self.assertEqual(doc.doc['vars_dont'].docstring, '')
         self.assertIn('integer', doc.doc['but_clss_have_doc'].docstring)