update docs

Author: czardoz

Doc/howto/perf_profiling.rst

@@ -24,7 +24,8 @@ functions to appear in the output of the ``perf`` profiler. When this mode is
 enabled, the interpreter will interpose a small piece of code compiled on the
 fly before the execution of every Python function and it will teach ``perf`` the
 relationship between this piece of code and the associated Python function using
-`perf map files`_.
+`perf map files`_. If you're an extension author interested in having your extension
+write to the perf map files, refer to :doc:`the C-API <../c-api/perfmaps.rst>`.
 
 .. note::
 

Misc/NEWS.d/next/C API/2023-04-14-23-05-52.gh-issue-103295.GRHY1Z.rst

@@ -1,3 +1,5 @@
 Introduced :c:func:`PyUnstable_WritePerfMapEntry`, :c:func:`PyUnstable_PerfMapState_Init` and
 :c:func:`PyUnstable_PerfMapState_Fini`. These allow extension modules (JIT compilers in
-particular) to write to perf-map files in a thread safe manner.
+particular) to write to perf-map files in a thread safe manner. The
+:doc:`perf profiling feature <../howto/perf_profiling.rst>` also uses these APIs to write
+entries in the perf-map file.