[ci skip] Add changelog for rti mixing

Author: rjfarmer

docs/source/changelog.rst

@@ -138,6 +138,18 @@ This was found to be important for smooth convective boundary
 evolution with convective premixing.
 
 
+RTI
+~~~
+
+A bug has existed since shortly after r15140 where RTI
+mixing will be effectively zero in a model even with the
+``RTI_flag=.true.`` set.
+
+This has now been fixed. Users of RTI mixing are recommended to upgrade to the
+newest MESA version.
+
+See `gh-503 <https://github.com/MESAHub/mesa/issues/503>`_
+
 
 Changes in r22.11.1
 ===================

docs/source/known_bugs.rst

@@ -31,7 +31,7 @@ See `gh-491 <https://github.com/MESAHub/mesa/issues/491>`_ and `gh-497 <https://
 RTI
 ===
 
-A bug has existed since shortly after r15140 where RTI mixing will be effectively zero in a model even with the RTI_flag=.true.
+A bug has existed since shortly after r15140 where RTI mixing will be effectively zero in a model even with the ``RTI_flag=.true.``
 
 This has now been fixed in the git main.