TSQL: Add indentation for UPDATE statement

[jpers36]

Brief summary of the change made

Adding Indent/Dedent tags for TSQL's UPDATE statement.

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

None.

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.

[codecov]

Codecov Report

Merging #2532 (75f2f0b) into main (378932f) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main     #2532   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          162       162           
  Lines        11700     11700           
=========================================
  Hits         11700     11700           

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

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