[3.12] gh-123570: Add link to weakref.ref from weakref_slot docs in dataclasses (GH-123571) (#123595)

gh-123570: Add link to `weakref.ref` from `weakref_slot` docs in `dataclasses` (GH-123571)
(cherry picked from commit c3ed775)

Co-authored-by: sobolevn <[email protected]>

Author: miss-islington

Doc/library/dataclasses.rst

@@ -215,7 +215,8 @@ Module contents
 
    - *weakref_slot*: If true (the default is ``False``), add a slot
      named "__weakref__", which is required to make an instance
-     weakref-able.  It is an error to specify ``weakref_slot=True``
+     :func:`weakref-able <weakref.ref>`.
+     It is an error to specify ``weakref_slot=True``
      without also specifying ``slots=True``.
 
     .. versionadded:: 3.11