App drawer scroll bar optimization

Describe the feature

Make the side scroll bar (alphabet index) support "haptic feedback pop-ups" - when you slide your finger over a letter, that letter pops out from the side and expands for display. (I'm using a translator, so it might not be entirely accurate.)

Why would it be useful to add?

It makes it easier to see which letter is currently selected, and the old scroll bar was really hard to use

Did the feature exist in Lawnchair Legacy?

Yes

Example(s)

                  A
                  B
               C
                  D
                  E

C is the position where the finger is selected

Additional context

No response