Paper cuts collection

[ChrisPenner]

@aryairani asked that I collect up the paper cuts from a recent discussion:

• [x] Better project-tab-complete for merge: https://github.com/unisonweb/unison/pull/4513
• [x] Better/more complete tab-completion coverage
• [x] Better/more complete fzf-completion coverage
• Maybe allow bare project slugs to resolve to full project names with a user handle, e.g.:
  • switch nimbus should succeed even though it's called @cloud/nimbus
• record type round-trip
  • think this has to do with edit, and not with update. e.g. edit <type> <accessor>
  • either apply the same fix to edit as to update, or maybe edit.namespace
• [in progress] Editing definitions with symboly intermediate name segments (e.g. edit Nat.(+).doc)
  • There is past work, but it'll likely need to be restarted
• Need a way to copy code between branches / projects — travis has started
• [ ] #5444
• pretty-print is way too slow — chris says probably global name-lookup related
• [x] #5445
• pipelining postgres queries in the db client library
• diff between branches "that's somehow just the stuff you care about" — talk to stew/cody for more info. possibly means ignore lib? or summarize lib changes

[stew]

• tab completion / fzf for dependents

[ChrisPenner]

@stew That'll be patched in https://github.com/unisonweb/unison/pull/4519 🎉