Fixed #26679 -- Documented which methods are disabled on RelatedManager if there's an intermediate table.

docs/ref/models/relations.txt

@@ -166,8 +166,9 @@ Related objects reference
        on either end of the relationship.
 
        Also, if you are using :ref:`an intermediate model
-       <intermediary-manytomany>` for a many-to-many relationship, some of the
-       related manager's methods are disabled.
+       <intermediary-manytomany>` for a many-to-many relationship, then the
+       ``add()``, ``create()``, ``remove()``, and ``set()`` methods are
+       disabled.
 
 Direct Assignment
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