Scale spell window to spell list and terminal size

[Kilvoctu]

Summary

SUMMARY: Interface "Scale spell window to spell list and terminal size"

Purpose of change

Reduce amount of scrolling when screen space allows
Improve usability on small terminal size
Fixes #78802

(I accidentally screwed up #78871 by merging a different branch into it, instead of the other way around, so I'm remaking the PR)

Describe the solution

Give the spells window more space to show spell descriptions by default.
As more spells populate the list, the window's vertical size increases, up to 90%.
For smaller terminal sizes, the spells window will shrink as needed to fit.

Describe alternatives you've considered

Use the entire vertical space of the screen if needed
Not increasing height to accomodate description

Testing

Game compiles and loads
Create character and debug in spells
Test varying spell list amounts at multiple terminal sizes
Scroll through spell tabs

Additional context

Before, fresh install build 76c2d10
Maximum terminal

After
Max terminal

With many spells

With one spell

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Before
Minimum terminal

After
Min terminal

With one spell