Setting a maximum width

[austinbutler]

I see reference to ideal_writing_area_width and just_do_it_for_me in issue, but it seems it's no longer in the code. I assume these were removed in the rewrite. How would one achieve similar results with the current configuration options? I have an ultrawide monitor, and all true-zen modes result in 300+ character line lengths.

Something like an ideal writing area range as mentioned in the issue above would be... ideal.