added changes entry and versionchanged code docs

CHANGES.rst

@@ -7,7 +7,7 @@ Unreleased
 Version 2.2.3
 -------------
 
-Unreleased
+-   Added reset_blueprint method to prevent error and warning when using test-scoped app fixtures :issue:`#4786`
 
 
 Version 2.2.2

src/flask/blueprints.py

@@ -472,6 +472,8 @@ class Blueprint(Scaffold):
     def reset_blueprint(self):
         """Resets this blueprint. Clears registered child blueprints and
         set _got_registered_once flag to False
+
+        .. versionchanged:: 2.2.3
         """
         self._blueprints = []
         self._got_registered_once = False