Add a title to the picker

[LeoniePhiline]

The picker is entirely void of context.

You have no indication:

• what kind of picker it is at all
• what the searched symbol is if it is a "show references" (LSP) picker. (gi)
• which base dir it is searching from Space-f/F
• etc.

Adding a picker title field and fill it with an appropriate string for each picker use could really help give some orientation.

[CptPotato]

I would prefer this to be an option. I usually know what I get when using each specific picker and prefer the more minimal aesthetic.

I even thought about styling the picker to be border-less (or using a single collapsed border in the center).
I've been using a more minimal window style for a while now and quite like it:

screenshot