Replace Gamma Adjustment with Brightness Adjustment

[kphoenix137]

Gamma adjustment is extremely ugly. Replaced it with a more refined system that preserves the look of the game, but makes it less dark and easier to see on low brightness displays.

100% brightness level was configured to closely match the "intensity" of gamma at 100%. This is roughly a 100% brightness increase in the midtones from the vanilla pallette, with varying brightness increases in the low tones and high tones.

[kphoenix137]

My clang formatting script doesn't agree with what CI thinks is proper clang formatting apparently.

[StephenCWills]

We recently bumped from clang-format-13 to clang-format-18, which did tweak some rules. Try to match the version as closely as possible.

[kphoenix137]

@AJenbo can you re-run tests?

[StephenCWills]

That red x was making you anxious, huh?

[AJenbo]

This is a lot nicer then what I expected, I thought you might have just renamed "Gamma" to "Brightness" to make it "easier" to understand :D

[kphoenix137]

This is a lot nicer then what I expected, I thought you might have just renamed "Gamma" to "Brightness" to make it "easier" to understand :D

Expectations have never been lower 🥲

[AJenbo]

Feed back from a visually impaired player:

this second one does seem better, for me the original gamma isn't too much of an issue, I think? The big stuff for me in this case is the text elements, and other UI menus, and those look pretty good when I ran them at a lower resolution.

So this fit very well with the 1.6.0 goals :)