[FEATURE] Better floating window focusing method

[qlibp]

Is your feature request related to a problem? Please describe. Situations: multiple float window(not sure if it's the common case) We could easily focus on any popup window with mouse, but, with keyboard, we need w to cycle through all the windows to finally reach our destination float window as we can't get the float window id easily.

Describe the solution you'd like Method 1: The easiest way, but more cmd needed: when opening the window, we could get the window num, but we need a way to show that window number on ui, maybe shown on the win title? And when we want to focus, we mannually enter that win num

Method 2: The more intuitive way, when we press prefix key, the float window ui shows up some pre-define alphabets, after we press the wanted alphabet, we focus on that float window.

Method 3: Just mentioning that, we could keep the win num in a list, and provide a cycle keybind to cycle through all the goto-preview floating window.

Describe alternatives you've considered No

Additional context No

[qlibp]

works fine with nvim-window-picker v2.*