Update regex of VSCode grammars to be used with `github/linguist`

As of right now, syntax highlighting is broken on GitHub for anything inside <script>, <style>, and <template> tags in .svelte files.

This started (I believe) with this PR: https://github.com/github/linguist/pull/5963. That points the source for svelte files to https://github.com/sveltejs/svelte-atom. However, there is apparently some bug in the injections section of that grammar that is breaking syntax highlighting (https://github.com/github/linguist/issues/5830#issuecomment-1195653540).

Since Atom is going to be sunsetted, and the VSCode grammars in this repo use TextMate grammar, I was going to open a PR in github/linguist to update the source to point to the grammars here. However, when I attempted to add it to that repo, it failed linguist’s compiler check with these errors:

- Invalid regex in grammar: `markdown.svelte.codeblock.script` (in `packages/svelte-vscode/syntaxes/markdown-svelte-js.json`) contains a malformed regex (regex "`(?<=script.*>)(?!</)`": lookbehind assertion is not fixed length (at offset 13))
- Invalid regex in grammar: `svelte.pug.tags` (in `packages/svelte-vscode/syntaxes/pug-svelte-tags.json`) contains a malformed regex (regex "`\b(?<=[\w$\-_]*)\s*?(!=|=)\s*?([`...": group name must start with a non-digit (at offset 56))
- Invalid regex in grammar: `svelte.pug.tags` (in `packages/svelte-vscode/syntaxes/pug-svelte-tags.json`) contains a malformed regex (regex "`\b(?<=[\w$\-_]*)\s*?(!=|=)\s*?([`...": group name must start with a non-digit (at offset 58))
- Invalid regex in grammar: `svelte.pug.tags` (in `packages/svelte-vscode/syntaxes/pug-svelte-tags.json`) contains a malformed regex (regex "`\b(?<=[\w$\-_]*)\s*?(!=|=)\s*?(?`...": lookbehind assertion is not fixed length (at offset 15))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=^\s*?|#\[\s*?|:\s+?)([A-Z][a`...": lookbehind assertion is not fixed length (at offset 9))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=^\s*?|#\[\s*?|:\s+?)([A-Z][a`...": lookbehind assertion is not fixed length (at offset 9))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=^\s*?|#\[\s*?|:\s+?)(\+)(deb`...": group name must start with a non-digit (at offset 104))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=each\s*?\(\s*?')(.*)\s+?(as\`...": lookbehind assertion is not fixed length (at offset 19))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=each\s*?\(\s*?')(.*)\s+?(as\`...": lookbehind assertion is not fixed length (at offset 19))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=await\s*?\(\s*?')(.*)\s+?(th`...": lookbehind assertion is not fixed length (at offset 20))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=debug\s*?\(\s*?')(\w+?)(,|$)`": lookbehind assertion is not fixed length (at offset 20))
- Invalid regex in grammar: `svelte.pug` (in `packages/svelte-vscode/syntaxes/pug-svelte.json`) contains a malformed regex (regex "`(?<=^\s*?|#\[\s*?|:\s+?)(\+)(els`...": lookbehind assertion is not fixed length (at offset 9))
- Invalid regex in grammar: `markdown.svelte.codeblock.style` (in `packages/svelte-vscode/syntaxes/markdown-svelte-css.json`) contains a malformed regex (regex "`(?<=style.*>)(?!</)`": lookbehind assertion is not fixed length (at offset 12))

I admittedly know nothing about TextMate grammars and only basic regex, but I was wondering if these are things that could be changed/fixed so that we can point linguist here to fix syntax highlighting? If not, we can close this. Thanks!

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RELATED ISSUES:

• https://github.com/sveltejs/svelte-atom/issues/20
• https://github.com/github/linguist/issues/5830
• https://github.com/community/community/discussions/13004
• https://github.com/community/community/discussions/20556

[kindoflew]

Hopefully last update: I added a fix to the syntax for injections in svelte-atom (https://github.com/sveltejs/svelte-atom/pull/21) and thanks to @umanghome’s fork of NovaLightshow, we have soft confirmation that it works. The maintainer of github/linguist says the next release will be the week of Nov 14 the earliest, so hopefully we get syntax highlighting back before Christmas 😂.

Closing this as it’s being solved in other repos. Thanks for the help everyone!

[umanghome]

I’m working on updating the VS Code grammar to make it usable with linguist.