Add ALGOL

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Description

Adding ALGOL as a "new" language.
Note that ALGOL 60 and ALGOL 68 don't have the necessary popularity to be added seperatly at the moment, but we can add them later.

Closes #7196

Checklist:

• I am adding a new language.
  • The extension of the new language is used in hundreds of repositories on GitHub.com.
    • Search results for each extension:
      • 1.2k files: https://github.com/search?q=path%3A*.alg+AND+%28%2F%5Ecomment%5Cb.*%28%3B%7Ccomment%29%2F+OR+%2F%5Ebegin%5B%5Cs%5CS%5D*%5Eend%2F+OR++%2F%5Cb%28integer%7Creal%7Cboolean%7Cstring%29%5Cb%5Cs%2B%5Cw%2B%5Cs*%3A%3D%5Cs*%2F+OR+%2F%5E%23%5B%5E%23%5Cn%5D%2B%23%24%2F%29+NOT+is%3Afork+NOT+user%3Aacmeism&type=code
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • https://github.com/ailrk/blgol60/blob/04398762ef256906dc2be69a9ec8b43d9ddd19d2/data/examples/example15.alg
    • Sample license(s): MIT
  • I have included a syntax highlighting grammar: https://github.com/PolariTOON/language-algol60?rgh-link-date=2025-01-09T00%3A10%3A49.000Z
  • I have added a color
    • Hex value: #D1E0DB (very light green)
    • Rationale: Color of the publication shown here
  • I have updated the heuristics to distinguish my language from others using the same extension.

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I've updated the search query at the top of the PR with the new regex for ALGOL 68 comments and we are now at 2.1k results.

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If we exclude the user acmeism from search, the total falls back to 1.2k files, so it seems that the popularity threshold has not been reached actually. ALGOL will have to wait a little longer, but it has been around for more than 60 years, so what's a few more years of wait, right? 😅