This particularly prevents the initial error all users will see when the
app first loads.

TODO: implement something more elegant.

This reverts commit 4c784b32c8.

This reverts commit c3b0a35a2e.

Opening a text file would overwrite the current draft, so for now we'll
disable this.

- Mention User Guide
- Mention CLI dependence
- Improve meson install instructions

Requires writeas-cli v1.1

Right now this mostly just includes (most importantly) undo/redo,
and less importantly smarter deletion and keyboard navigation.

Because changing the background colour of a textview for some reason
causes text selection not to show. This is a documented issue others
experience.

This code could be refactored a little now, but it works for the
elementary and HighContrast themes.

Because for some reason this would happen seemingly at random before.
No idea why. But I did test that it occurs during save, not read.

And it doesn't appear to happen anymore.

This is manually computed, because GTK is just complaining it doesn't support percentages.