Support indenting WINDOWS clauses and (optionally) CTEs

[tunetheweb]

Brief summary of the change made

Fixes #2600

Are there any other side effects of this change that we should be aware of?

WINDOWS clauses will now indent (similar to other main clauses) which may cause some extra rules to flag for those that don't indent them.

Pull Request checklist

• Please confirm you have completed any of the necessary steps below.

• Included test cases to demonstrate any code changes, which may be one or more of the following:

  • .yml rule test cases in test/fixtures/rules/std_rule_cases.
  • .sql/.yml parser test cases in test/fixtures/dialects (note YML files can be auto generated with tox -e generate-fixture-yml).
  • Full autofix test cases in test/fixtures/linter/autofix.
  • Other.

• Added appropriate documentation for the change.

• Created GitHub issues for any relevant followup/future enhancements if appropriate.

[codecov]

Codecov Report

Merging #2601 (f16c1bd) into main (14e80e5) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main     #2601   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          163       163           
  Lines        11894     11894           
=========================================
  Hits         11894     11894           

Impacted Files	Coverage Δ
src/sqlfluff/dialects/dialect_ansi.py	100.00% <ø> (ø)
src/sqlfluff/dialects/dialect_tsql.py	100.00% <ø> (ø)

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[elyobo]

Tested your branch and confirmed it's looking good, thank you very much for this.