apply consistent ORM mutable notes for all mutable SQL types

apply consistent ORM mutable notes for all mutable SQL types

in
https://github.com/sqlalchemy/sqlalchemy/discussions/8447
I was surprised that we didnt have any notes about using Mutable
for ARRAY classes, since we have them for HSTORE and JSON.

Add a consistent topic box for these so we have something to
point towards.

Change-Id: Idfa1b2cbee67024545f4fa299e4c875075ec7d3f