Fig is back in Q+, Revive clap_complete_fig?

[jeremiah-snee-openx]

fig spec is now being used by multiple projects, but clap_complete_fig has been removed

• Deprecate and remove clap_complete_fig? #5395 by @epage
• chore: Remove clap_complete_fig #5871

Should clap_complete_fig be revived?

Projects that use fig spec

• https://github.com/microsoft/inshellisense
• fig-spec now supported in vscode
• q-cli formerly fig (open-source by Amazon)