Actions: Refresh symbolic window actions

[wpkelso]

Addresses #928 by unifying the size and language of the window controls.

Previously, window-close used a baseline of 4px, window-minimize used a border of 3px, and window-maximize/window-restore both used 4px borders. This mostly unifies to 2px border, with window-close now using a 3px border because 2px felt slightly large in comparison to the others

Additionally, window-minimize used an older shape language and color, so that has been unified as well.

In context:

[danirabbit]

I think this makes the close button too big. Especially apparent here:

Seems way larger than the plus icon

[wpkelso]

Slightly decreased the size of the arms to find a middle-ground between the two sizes, though I think it may have caused some pixel-fitting issues :(

Extra reference of what size is currently like on main, for the sake of it: