Mark in whatsnew

Author: clin1234

Doc/whatsnew/3.16.rst

@@ -510,6 +510,8 @@ mimetypes
 * Valid extensions start with a '.' or are empty for
   :meth:`mimetypes.MimeTypes.add_type`.
   Undotted extensions now raise a :exc:`ValueError`.
+* Add more MIME types
+  (Contributed by Charlie Lin in :gh:`146344`.)
 
 shutil
 ------