fix: add missing syntax definitions for mdn-data

[xbinaryx]

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What is the purpose of this pull request?

Updating mdn-data from 2.23.0 to 2.27.1 introduced new syntax references that were not defined in css-tree's local compatibility patch layer. As a result, the default lexer started failing validation with unresolved <syntax>, <attr-unit>, and <autospace> references.

What changes did you make? (Give an overview)

Added the missing syntax definitions for syntax, attr-unit, and autospace in data/patch.json.

Related Issues

#119

Is there anything you'd like reviewers to focus on?

[DMartens]

This PR has some overlap with #117 (e.g. the autospace definition).
I think we should first land the other PR and then rebase this PR on it.

[nzakas]

Probably now should wait to merge #125

[github-actions]

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[DMartens]

@xbinaryx Can you please rebase on the main branch as #125 was merged and there are now conflicting files.

[github-actions]

Hi everyone, it looks like we lost track of this pull request. Please review and see what the next steps are. This pull request will auto-close in 7 days without an update.

[lumirlumir]

@xbinaryx Are you still working on this?