Enhancement: Strumline background option

[Average-FNF-Modder]

What is your suggestion, and why should it be implemented?

Some peeps can have a hard time seeing the notes with all the chaos going on in the background, so if we could have like a black rectangle underlay for the note lane that you can change the opacity of for a little more accessibility and readability for the people who need it that would be neat.

[Hundrec]

Sounds like a great accessibility option!

I'm not sure what the devs think about difficulty-altering options (out of potential unfairness), but I agree with this suggestion.

[NotHyper-474]

#2949 implements this!

[TheDrawingCoder-Gamer]

Sounds like a great accessibility option!

I'm not sure what the devs think about difficulty-altering options (out of potential unfairness), but I agree with this suggestion.

in etterna things like this don't affect your score at all. visuals don't really affect that much

[AbnormalPoof]

#4166 (comment):

A version of this commit with an identical changelist (but a different commit ID, maybe it got rebased) was already approved and merged internally, so expect to see it in v0.6.