python: unify change notes with fixes

Author: yoff

python/ql/lib/change-notes/2022-11-14-grouped-exceptions-breaking.md

@@ -2,3 +2,4 @@
 category: fix
 ---
 * `except*` is now supported.
+* The result of `Try.getAHandler` and `Try.getHandler(<index>)` is no longer of type `ExceptStmt`, as handlers may also be `ExceptGroupStmt`s (After Python 3.11 introduced PEP 654). Instead, it is of the new type `ExceptionHandler` of which `ExceptStmt` and `ExceptGroupStmt` are subtypes. To support selecting only one type of handler, `Try.getANormalHandler` and `Try.getAGroupHandler` have been added. Existing uses of `Try.getAHandler` for which it is important to select only normal handlers, will need to be updated to `Try.getANormalHandler`.