feat(theme-common): code block MagicComments support for TeX/LaTeX/Matlab

[jj-style]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

I could not see an open issue for it but I would like to be able to use the magic comments feature in Matlab code blocks. This isn't currently supported due to Matlab's way of commenting, therefore I have added this capability in this PR.

Test Plan

• I have added a Matlab code snippet in the
  dogfooding page which verifies the functionality.
• I ran a local instance of the site and verified that the lines were not highlighted by the magic comments
• I did the implementation and restarted the server and verified that the lines were highlighted

before

after

Test links

Deploy preview: https://deploy-preview-8982--docusaurus-2.netlify.app/tests/pages/code-block-tests/#magic-comments-tests

Related issues/PRs

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
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[Josh-Cena]

Thanks! This pattern is inherited from TeX so let's call the style tex and add tex and latex to the language list.

[jj-style]

Thank you for the feedback!
I have now changed the comment style to be called tex and added an example in dogfooding code blocks page to verify this for latex also

[slorber]

LGTM thanks 👍

[jj-style]

Thanks for the review and for pushing up the missing quote! 😊