Keep GRANT and REVOKE privilege clauses together when reindenting

[adenzhou1350]

reindent=True treats permission names such as SELECT as new statements and REVOKE's FROM as a query clause:

REVOKE
SELECT ON TABLE customers
FROM umbrella;

Keep those boundaries together when the statement starts with a DCL keyword. Nested groups still use the existing formatter, and subsequent SELECT statements retain normal indentation. Token classification is unchanged: GRANT/REVOKE remain DCL and SELECT remains DML.

Fixes #409. This is separate from the keyword-classification change discussed in #719.

Validation on native Windows Python 3.14.3:

• The same 12 regression/control cases: 10 fail and 2 pass on unchanged master; all pass with this change.
• Full suite: 518 passed, 2 xfailed, 1 xpassed (existing xfail/xpass outcomes unchanged).
• Ruff and git diff --check pass.

Tests cover permission lists, REVOKE GRANT OPTION FOR, leading comments, keyword casing, repeat formatting, a following query, and unchanged lexical token types. This is a formatting test, not a live database authorization test.

• ran the tests (pytest)
• all style issues addressed (ruff)
• changes covered by tests
• changelog updated; no public API changes