Introduce Chroma syntax-generation script

[arusahni]

Motivation

• This PR adds a feature that has not yet been specified.
  Hugo uses Chroma for syntax highlighting. We upstreamed a Materialize-specific syntax to ensure our dialect's keywords are recognized as such. Now that the end-to-end change is in prod, let's automate the process of generating updates for the dialect lexer.

I have a PR filed against the Chroma repo that uses a version of the lexer generated by this script.

Tips for reviewer

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• 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:

no user facing behavior changes

[benesch]

Looks great! Thanks for making this usable by other folks on the team.