Changes from review

Author: colesbury

Doc/c-api/init.rst

@@ -2301,7 +2301,7 @@ The C-API provides a basic mutual exclusion lock.
       should not be used to make concurrency control decisions, as the lock
       state may change immediately after the check.
 
-   .. versionadded:: 3.14
+   .. versionadded:: next
 
 .. _python-critical-section-api:
 

Doc/whatsnew/3.15.rst

@@ -212,6 +212,13 @@ Porting to Python 3.15
 
   (Contributed by Serhiy Storchaka in :gh:`133595`.)
 
+* Private functions promoted to public C APIs:
+
+  * ``PyMutex_IsLocked()`` : :c:func:`PyMutex_IsLocked`
+
+  The `pythoncapi-compat project`_ can be used to get most of these new
+  functions on Python 3.14 and older.
+
 Deprecated C APIs
 -----------------