Add assist labels layout option under a settings menu

[topiasv]

The current keyboard layout doesn't have any guides on how to use the flick keyboard and no indication where one should swipe to get a certain kana/letter. Especially the alphabet and special characters layouts can get a while to get used to as it's difficult to remember which direction one should flick to get a certain character. So my suggestion for the problem is as follows:

1. Add assist labels that hint the user where each character reside in the flick layout
2. Add a settings entry for layout configuration for experienced users who don't need guides

Optional and nice to have features:

3. Modify the popper item to be able to show the flick guides as well
4. Use a custom highlight effect to signal the user which key is selected. (check google flick keyboard for reference)

I already have a prototype of the first feature so I can make a branch for you to test it. I tried implementing the flick guides feature for the popper but that seems to be very difficult. The popper feature requires a new file to patch so the drawback is added complexity but on the flip side the benefit is to be able to see the guides even when you have the key pressed.

[knokmki612]

1. Add assist labels that hint the user where each character reside in the flick layout
2. Add a settings entry for layout configuration for experienced users who don't need guides

Add assist labels is a good idea and this idea is well known by Gboard. So I think this idea is friendly for native speakers too.

This feature should be a default and no need to make a new option will be fine.