Add extension .code-workspace to the language JSON with Comments.

Description

Workspaces in Visual Studio Code

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*.code-workspace
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • https://github.com/sampotts/plyr/blob/cbd1596af4673a954051e0bfffdde7558dd24293/plyr.code-workspace
    • Sample license(s):
      • MIT