Add porting guide entry for fetch_url change in behavior (#76314)

docs/docsite/rst/porting_guides/porting_guide_core_2.13.rst

@@ -72,6 +72,12 @@ Noteworthy module changes
 No notable changes
 
 
+Breaking Changes
+----------------
+
+* ``ansible.module_utils.urls.fetch_url`` will now return the captured ``HTTPError`` exception as ``r``. ``HTTPError`` is a response like object that can offer more information to module authors. Modules should rely on ``info['status'] >= 400`` to determine if there was a failure, instead of using ``r is None`` or catching ``AttributeError`` when attempting ``r.read()``.
+
+
 Plugins
 =======