Refactor how tooltips are sized, items placed, margins calculated, etc.
Current code has some mistakes that we use kludges to compensate for,
and it doesn't properly consider the font size in calculating margins.
The result shown to users in normal circumstances (changing resolution
scale only) with this PR applied should look identical to current.
Small changes when the text style size is changed. However, this is
mostly to allow later adjustments to padding, which currently _breaks_
when changed.
Pull Request: https://projects.blender.org/blender/blender/pulls/134205
c663b78bcb