Text sizescale

[danirabbit]

• Based on Move Text settings to their own page #297

Fixes #289
Fixes #248

[cassidyjames]

Need to fix keyboard interactivity, I think I messed up resolving merge conflicts (and will try to fix that), and I have a question about the design:

Should we just go with the scale + spinbutton like we do in both Keyboard and Mouse & Touchpad settings? It seems like this is an appropriate place and would make it easier if you know a specific text scale works well on your machine versus having to just guess on a precise position based on the current design. I also think it would let us address my other inline comment about the start and end marks, since the scale would be even more self-evident.

I also think I'd actually like to try a less granular step; maybe snapping to every 0.125 instead of 0.05 because that feels really fiddly.

[danirabbit]

Yeah good call about the spin button

[danirabbit]

@cassidyjames thanks for the thorough review here! I changed things to match the design of scale + spinbutton we have in other views like Mouse & Touchpad. So, removed the labels, notches on top. I also changed the set method from button release on the scale to a timeout on the adjustment. This fixes the keyboard case and should still have the same effect of keeping the UI from doing a stuttering resize while you're still dragging.

Also reverted the previous merge and fixed that, so you might have conflicts when you pull sorry!

[cassidyjames]

Nice work, this seems a lot better.