Add MoonBit

[tonyfettes]

This pull request adds support to MoonBit programming language.

Description

This pull request adds support to MoonBit programming language. Here are some relevant resources:

• Website: https://www.moonbitlang.com
• GitHub Organization: moonbitlang

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 (I removed the KEYWORDS search because common keywords are widely used in other programming languages):
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.mbt
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • https://github.com/moonbit-community/moonbit-native-benchmark1
      • https://github.com/moonbit-community/moonbit-native-benchmark2
    • Sample license(s): Apache-2.0
  • I have included a syntax highlighting grammar: moonbitlang/moonbit-tmLanguage
  • I have added a color
    • Hex value: #b92381
    • Rationale: This is the color that they use to brand the MoonBit programming language. Similar colors are used in the icons for MoonBit, as you might see in their website.
  • I have updated the heuristics to distinguish my language from others using the same extension. (After some primitive search on GitHub, I don't think the extension .mbt is used by other languages).

[lildude]

LGTM. Thanks.

Note: this PR will not be merged until close to when the next release is made. See here for more details.

As an aside, there's no need to keep updating the grammar as we pull in the latest version whenever we make a new release.

[hustcer]

@tonyfettes Should .mbti extension be added also?

[lildude]

@tonyfettes Should .mbti extension be added also?

I've advise against it as usage is not sufficient for inclusion right now so adding it to this PR will delay this from being merged. Users can use an override as soon as this lands until usage meets requirements.

[tonyfettes]

@tonyfettes Should .mbti extension be added also?

@hustcer We are not planning to add .mbti extension in this PR. This file is produced by the moon info command to boost code-preview process, and is currently unstable.