gh-108267: Dataclasses docs: Fix object.__setattr__ typo (#108355)

Fixed a sentence in dataclasses.rst

Changed "__setattr__" to "object.__setattr__" in a section that was specifically supposed to refer to the __setattr__ method of the object class. Also suppressed the link to the data model docs for __setattr__, since we're talking about a specific __setattr__ implementation, not __setattr__ methods in general.

Doc/library/dataclasses.rst

@@ -609,7 +609,7 @@ methods will raise a :exc:`FrozenInstanceError` when invoked.
 
 There is a tiny performance penalty when using ``frozen=True``:
 :meth:`~object.__init__` cannot use simple assignment to initialize fields, and
-must use :meth:`~object.__setattr__`.
+must use :meth:`!object.__setattr__`.
 
 Inheritance
 -----------