improve pep-695 inference including Enum support

improve pep-695 inference including Enum support

Fixed issue in ORM Annotated Declarative where typing issue where literals
defined using :pep:`695` type aliases would not work with inference of
:class:`.Enum` datatypes. Pull request courtesy of Alc-Alc.

Fixes: #11305
Closes: #11313
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/11313
Pull-request-sha: 090f0d865c4129cffffbce6a6ce3db9b91602460

Change-Id: Iac63302ad74fd7018a34a50c80ec3aeb87dc94a4
(cherry picked from commit ce26cfa5d5253345a5f962359e5c742ea039c211)