PEP 800: Update reference implementation (python#4850)

Author: JelleZijlstra

peps/pep-0800.rst

@@ -373,10 +373,10 @@ Reference Implementation
 
 The runtime implementation of the ``@disjoint_base`` decorator is available in
 `typing-extensions 4.15.0 <https://pypi.org/project/typing-extensions/4.15.0/>`__.
-`python/mypy#19678 <https://github.com/python/mypy/pull/19678>`__
-implements support for disjoint bases in mypy and in the stubtest tool.
-`astral-sh/ruff#20084 <https://github.com/astral-sh/ruff/pull/20084>`__
-implements support for disjoint bases in the ty type checker.
+Mypy and its stubtest tool support the decorator as of version 1.18.1; this was implemented in
+`python/mypy#19678 <https://github.com/python/mypy/pull/19678>`__.
+Support was added to the ty type checker in
+`astral-sh/ruff#20084 <https://github.com/astral-sh/ruff/pull/20084>`__.
 
 Appendix
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