Add Skript Language (closes #6857)

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Add Skript language support with .sk files

Description

This PR adds support for the Skript language to Linguist; it is a scripting language for Minecraft servers. Via Skript, server owners, etc. can easily customize their servers, automate tasks & more. It has a user-friendly syntax close to English.

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:
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.sk (46.8k files)
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • https://github.com/SkriptLang/Skript/blob/master/src/main/resources/scripts/-examples/chest%20menus.sk
      • https://github.com/SkriptLang/Skript/blob/master/src/main/resources/scripts/-examples/text%20formatting.sk
      • https://github.com/SkriptLang/Skript/blob/master/src/main/resources/scripts/-examples/variables.sk
    • Sample license(s):
      • GNU General Public License for Skript repo
      • MIT for Skript Grammar repo
  • I have included a syntax highlighting grammar: https://github.com/SkriptLang/skript-grammar
  • I have added a color
    • Hex value: #FF9800
    • Rationale: used the same color from the "." in the Skript logo see here & here
  • [ ] I have updated the heuristics to distinguish my language from others using the same extension.

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I somehow missed #6559 so I put the PR in draft - whoops!

I'll see about picking up the next steps @/patHyatt laid out 👍

Looks like I'd have to add another ".sk" extension (probably skip) & a heuristic

Might be a fun side-project though! 👀