bpo-18085: Update refcounts.dat. (GH-11247)

Fixed some errors in refcounts.dat, remove functions removed in
Python 3, and add more entries for documented functions. This will
add several automatically generated notes about return values.

Doc/tools/extensions/c_annotations.py

@@ -87,7 +87,7 @@ def add_annotations(self, app, doctree):
             entry = self.get(name)
             if not entry:
                 continue
-            elif entry.result_type not in ("PyObject*", "PyVarObject*"):
+            elif not entry.result_type.endswith("Object*"):
                 continue
             if entry.result_refs is None:
                 rc = 'Return value: Always NULL.'