📝 Add a change note for PR aio-libs#561

Author: webknjaz

CHANGES/560.contrib.rst

@@ -14,3 +14,13 @@ Here's a usage example:
 
 For editable installs, this setting is on by default. Otherwise, it's
 off unless requested explicitly.
+
+The following produces C-files required for the Cython coverage
+plugin to map the measurements back to the PYX-files:
+
+.. code-block:: console
+
+    $ python -Im pip install -e .
+
+Alternatively, the `FROZENLIST_CYTHON_TRACING=1` environment variable
+can be set to do the same as the :pep:`517` config setting.

CHANGES/561.contrib.rst

@@ -0,0 +1,4 @@
+Coverage collection has been implemented for the Cython modules
+-- by :user:`webknjaz`.
+
+It will also be reported to Codecov from any non-release CI jobs.