Select items from history in Pickers (global_search)

[the-mikedavis]

Originally discussed in #11205

The refactored global_search picker from #9647 lets you accept the most recent item from history if there is something already in the history register (/ by default) and you hit Enter. It's useful to select other items from history too. Most minimally we need keybinds that go forward and backwards in the history, like A-n/A-p and/or A-down/A-up for example. In the long run it could also be nice to find a UI for the completions themselves, maybe something layering over the picker or a new pane that shows up when there are completions.

[xJonathanLEI]

Just to quickly quote @pascalkuthe on #11205:

The old.prompt doesn't shown a history either.

Actually it does:

I agree it can be tricky to get the UI done right in the picker context though.