bring back highlighting roms on rombrowser via alphabet

[RSw-Why]

Is your feature request related to a problem? Please describe.
In the previous version of mupen i have, you can (albeit a bit inconsistent) press a letter and mupen will highlight the first rom that starts with that letter. it is useful for me and probably others who tas romhacks and have a browser of up to 100+ roms in it. it seems in 1.1.5 you cannot do this.

2023-10-20.19-10-20.mp4

for the record, i only ever have "file name" column on, and im not sure how this would work with multiple columns with strings in, but it would be nice if you could make this work.