[emirmrkaljevic]

Fixes #888

In Transact-SQL, OUTPUT was not a reserved clause, so in UPDATE ... SET ... OUTPUT ... it got glued onto the end of the SET expression.

This adds OUTPUT to the Transact-SQL reserved clauses, so it starts a new line like INTO and WHERE (works for UPDATE, DELETE, INSERT and MERGE).

• New test covering UPDATE and DELETE with OUTPUT (and OUTPUT ... INTO).
• Updated the existing $action test (Using $action in tsql merge causes crash #810), since OUTPUT in MERGE now also starts its own clause.

pnpm test, pnpm run lint, pnpm run ts:check and prettier all pass.

[nene]

I'm adopting a new policy for this repository: no AI-generated contributions. I don't care how good they are.

This is to preserve my sanity.