Meta: change <ref> syntax

[domenic]

Although <ref> is nonstandard HTML, which is somewhat reasonable for build tools to use, requiring a nonstandard HTML parser for the build tools is kind of bad.

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The two commits in this PR were generated by:

1. Regexp replacing <ref[\s\n]+spec="?([^">]+)"?> with <ref>$1</ref>
2. Running specfmt.

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Merging this PR is delicate. I think the sequence will be:

• Merge Change <ref> syntax wattsi#152.
• Re-run CI on this PR. It should now work, because we pull the latest Wattsi on each CI run?
• Merge this PR. (Don't forget to squash.)
• Re-run the CI on Require the latest Wattsi html-build#280. It should now work, since whatwg/html is updated to use the new <ref> syntax.
• Merge Require the latest Wattsi html-build#280.

I can do all this, once the appropriate approvals are lined up. I'll be sure to carve aside an hour or two in case anything goes wrong and we need to revert.

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💥 Error: Wattsi server error 💥

PR Preview failed to build. (Last tried on Aug 6, 2023, 10:28 AM UTC).

More

PR Preview relies on a number of web services to run. There seems to be an issue with the following one:

🚨 Wattsi Server - Wattsi Server is the web service used to build the WHATWG HTML spec.

🔗 Related URL

Parsing MDN data...
Parsing...
Parse Error: (800,83) unexpected end tag

If you don't have enough information above to solve the error by yourself (or to understand to which web service the error is related to, if any), please file an issue.

[domenic]

I think the sequence will be:

For future reference, this did not work, because whatwg/html's CI relies on the GitHub Container Registry image for whatwg/html-build, which is only updated after successfully merging the html-build PR.

I had to resort to a sequence involving merging various PRs with failing CI, and then re-running the CIs after everything was merged.

But, it's all working now!