Python: Update change note

Author: tausbn

python/change-notes/2021-07-28-port-RoDoS-queries.md

@@ -1,3 +1,3 @@
 lgtm,codescanning
-* Added _Inefficient regular expression_ (`py/redos`) query, which is already available in JavaScript.
-* Added _Polynomial regular expression used on uncontrolled data_ (`py/polynomial-redos`), which is already available in JavaScript.
+* Added an experimental _Inefficient regular expression_ (`py/redos`) query, which is already available in JavaScript.
+* Added an experimental _Polynomial regular expression used on uncontrolled data_ (`py/polynomial-redos`), which is already available in JavaScript.