sql-parser: add parens after SET/RESET in ALTER CONNECTION

[benesch]

For consistency with ALTER ... {SET | RESET} in other commands.

Motivation

• This PR refactors existing code.

Tips for reviewer

@sploiselle apologies if I missed a design discussion about this! I have a vague recollection of talking about this way back when but the design document for ALTER CONNECTION seems to have disappeared?

Marking as a release blocker for the next release (v0.79) so we don't accidentally ship the syntax without the parens.

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered.
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• This PR includes the following user-facing behavior changes:
  • n/a as long as this makes v0.79

[sploiselle]

@benesch I accidentally deleted the design document for ALTER CONNECTION and didn't realize it until it was too late. I don't recall this being discussed, but I might be wrong. At any rate, appreciate the catch here.

[benesch]

@benesch I accidentally deleted the design document for ALTER CONNECTION and didn't realize it until it was too late.

Is it worth dredging it out of the Git history and merging it? 4e7364e is the commit I was able to find. If the final implementation deviated substantially from what was proposed there then it's probably not worth it!

I don't recall this being discussed, but I might be wrong. At any rate, appreciate the catch here.

We very lightly discussed it here, but GitHub hid those comments away when the design doc went missing!

At any rate, appreciate the catch here.

Thanks for the review and merge!