Description

Adds a grammar for Polar, a declarative logic programming language specialized for authorization logic.

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?utf8=%E2%9C%93&type=Code&ref=searchresults&q=extension%3Apolar+NOT+nothack
      • We expect most repos to use a single .polar file, representing the authorization rules for that repo, although some repos may split their authorization logic into a small number of additional .polar files.
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • gitclub.polar: https://github.com/osohq/gitclub/blob/main/backends/rails/app/policy/authorization.polar
      • gitcloud.polar: https://github.com/osohq/gitcloud/blob/main/policy/authorization.polar
    • Sample license(s): Apache 2.0
  • I have included a syntax highlighting grammar: https://github.com/osohq/polar-grammar