Add support for Pkl

[sgammon]

Adds support for the new Pkl configuration language from Apple.

Description

Credit to:

• @darvld and myself from the Elide team for assembling the tests + linguist changes
• @nishtahir for the textmate grammar
• @pixelcmtd for the feature request issue at Add support for the Pkl configuration language #6705

Fixes and closes #6705
Fixes and closes apple/pkl#155

Changelog

• feat: language support for Apple Pkl with textmate bundle
• feat: heuristics to distinguish with Python Pickle
• test: tests/samples for Apple Pkl configuration language

Checklist:

• I am adding a new extension to a language.

  • The new extension 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*.pkl
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a change to the heuristics to distinguish my language from others using the same extension.

• 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:
      • Here, but it is hard to distinguish Pkl sources from Pickle (Python) data
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • Samples from the official apple/pkl-go-examples
    • Sample license(s): Apache 2.0
  • I have included a syntax highlighting grammar: Grammar here
  • I have added a color
    • Hex value: #6b9543
    • Rationale: Main color (outer gear green) used in the Pkl project icon
  • I have updated the heuristics to distinguish my language from others using the same extension.

• I am fixing a misclassified language

  • I have included a new sample for the misclassified language:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a change to the heuristics to distinguish my language from others using the same extension.

• I am changing the source of a syntax highlighting grammar

  • Old: [URL to grammar repo]
  • New: [URL to grammar repo]

• I am updating a grammar submodule

• I am adding new or changing current functionality

  • I have added or updated the tests for the new or changed functionality.

• I am changing the color associated with a language

  • I have obtained agreement from the wider language community on this color change.
    • [URL to public discussion]
    • [Optional: URL to official branding guidelines for the language]

[lildude]

See inline comments.

Also:

Here, but it is hard to distinguish Pkl sources from Pickle (Python) data

Search accepts regexes now so you can use your heuristic to confirm popularity.

[lildude]

Whoops. There should only be one new addition and the file should be alphabetised (that's what the script/add-grammar script does. This last entry shouldn't be here.

[lildude]

This looks waaaay too loose as it'll match those first few strings anywhere in the line, eg it'll match "this new language is pkl" or "I came first in my class" or "this functionality is awesome" or "imported cheese smells". You probably don't want this 😉.

[lildude]

Oh yes, and we're going to also need a test for the heuristic.

[stackoverflow]

Hi @sgammon. We're preparing a PR for linguist, it should come soon. The grammar you are using in this submission is our current vscode one, which is pretty bare bones, we have a updated version of it now.

[sgammon]

@stackoverflow Ah, good to know 😄. We can close this PR or point at the new grammar, entirely up to you guys.

[sgammon]

Closing for now, can re-open if needed