Theme override for line spacing

[Crystal2002]

Is your feature request related to a problem? Please describe.
Currently, the client (apparently) figures out the line spacing based on what font is used. All I'm asking is that there be a theme setting override for what the distance between lines are. See the below screenshots for a better idea of what I'm complaining about.

Additional context

The left is the 1st, the right is the donor theme that the message lines came out of for the 2nd screenshot

Fonts to Test with here

[oldmud0]

Apparently not possible with Qt CSS. This solution should work though