Docs: Mention that Py_UNREACHABLE was added in 3.7 (#4337)
The macro was added for bpo-31338 in commit b2e5794870eb4728ddfaafc0f79a40299576434f
diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst
index e654c4c..de7139b 100644
--- a/Doc/c-api/intro.rst
+++ b/Doc/c-api/intro.rst
@@ -106,6 +106,8 @@
all possible values are covered in ``case`` statements. Use this in places
where you might be tempted to put an ``assert(0)`` or ``abort()`` call.
+ .. versionadded:: 3.7
+
.. c:macro:: Py_ABS(x)
Return the absolute value of ``x``.