A couple more small docstring refinements

- Single vs. double backtick error/inconsistency in one place
  (parameter names were in in doubled backticks, now single)

- Undo making "Iterator" in the phrase "Iterator yielding" a
  reference to collections.abc.Iterator, which is unnecessary and
  not done anywhere else.

git/config.py

@@ -920,8 +920,8 @@ def rename_section(self, section: str, new_name: str) -> "GitConfigParser":
         :raise ValueError:
             If:
 
-            * ``section`` doesn't exist.
-            * A section with ``new_name`` does already exist.
+            * `section` doesn't exist.
+            * A section with `new_name` does already exist.
 
         :return:
             This instance

git/util.py

@@ -1257,7 +1257,7 @@ def iter_items(cls, repo: "Repo", *args: Any, **kwargs: Any) -> Iterator[T_Itera
         keyword arguments, subclasses are obliged to to yield all items.
 
         :return:
-            :class:`~collections.abc.Iterator` yielding Items
+            Iterator yielding Items
         """
         raise NotImplementedError("To be implemented by Subclass")