miscellaneous to type dialects

miscellaneous to type dialects

Type of certain methods that are called by dialect, so typing dialects is easier.

Related to https://github.com/sqlalchemy/sqlalchemy/pull/12164

breaking changes:

- Change modifiers from TextClause to InmutableDict, from Mapping, as is in the other classes

Closes: #12231
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/12231
Pull-request-sha: 514fe4751c7b1ceefffed2a4ef9c8df339bd9c25

Change-Id: I29314045b2c7eb5428f8d6fec8911c4b6d5ae73e
(cherry picked from commit 4418ef79104a0e4591ff8268d75f1deb59bfcec3)