Add `gem` completion spec

[Alan Syue]

Sanity checks

• My issue relates to a specific CLI completion spec (e.g. git checkout is missing options in git completion spec). If your issue is more general, please create your issue here: withfig/fig
• I have searched github.com/withfig/autocomplete/issues and there are no duplicates of my issue
• I would like to work on this.

What CLI tool does this relate to?

gem

Which statement makes the most sense?

This completion spec does not exist

Issue Details

reference: https://guides.rubygems.org/command-reference/

[Robert Clover]

Wow, it's kinda wild that we don't already support this! Yes gem would be amazing, would really appreciate if you could contribute it 🤩

[Robert Clover]

Generator for listing gems:

const gems: Fig.Generator = {
  trigger: () => true,
  custom: async (tokens, executeShellCommand) => {
    const searchTerm = tokens[tokens.length - 1];
    const out = await executeShellCommand(
      `gem search --both --no-versions --no-details --quiet --norc '${searchTerm.replace("'", `'"'"'`)}'`,
    );
    return out.trim().split("\n")
      .filter((line) => line && !line.startsWith("*"))
      .map((name) => ({ name }));
  },
};

Make sure you put debounce: true on the arg containing the generator!

I'd be happy to accept a PR containing only the subcommands and their args, should be possible to knock that out in a couple mins

[Alan Syue]

OK, thanks! I'd love to work on it.