[PATCH 1/2] completion: more complete completion for zsh.

[Vincent Breitmoser]

Ah, that's a bit annoying.

What we could do is just stupidly load all addresses and work from there?  On my
machine, `notmuch address --deduplicate=address --output=address '*'` takes 0.25
seconds for a result set of 5500 addresses.

Could also put that result set in the zsh completion cache, for slightly less
live but immediate results on repeated calls. Is there a simple way to figure
out on the notmuch cli if a result we received is still fresh?

 - V