✨ Line highlight should appear behind ruler

[austincondiff]

The highlight should extend into the ruler rather than start after it ends.

Left: Xcode | Right: CodeEdit

This may or may not require #127.

[austincondiff]

Note: this may need to be a separate background behind the line number that lines up with the background behind the code on the right of it.

I say this because what would happen if there was horizontal overflow and the user scrolls to the right. The code would need to go underneath the fixed ruler view and the ruler view would need it's own active line indicator for that to be possible.

[Eliulm]

I would like to work on this issue