Shell completion doesn't complete subcommand-specific options when subcommand is abbreviated

[vincentdephily]

Eg emlop stats --a<tab> completes the --avg flag but emlop s --a<tab> doesn't. Checked for bash only. This is arguably an upstream clap bug, but I'd like to track it here.

[vincentdephily]

Emlop now ships its own completions, so this is no longer considered an upstream clap bug.

• Fixed for bash.
• Shouldn't be too hard for fish, just need to fork our own __fish_seen_subcommand_from, maybe ask the community
• Zsh is much too complex for me, help wanted (not just for the papercut mention in this bug)