`adjust-cursor-thickness` should apply to `cursor-style = underline`

[qwerasd205]

Discussed in https://github.com/ghostty-org/ghostty/discussions/3194

^{Originally posted by zx8 December 26, 2024} Coming from this answer, it appears this option already applies to the thickness of the cursor when the style is set to bar, but it does not apply when the cursor style is set to underline.

Here's how it looks between iTerm (left) and Ghostty (right) at the moment:

Would it be possible to extend this setting to work with underline mode too?

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Maintainer note

This is a limitation of the fact that we currently use the underline sprite drawing function to draw the underline cursor, which uses the underline thickness. This can be remedied by separating out the underline cursor drawing to live in the same place as the other cursor drawing functions, and use the cursor thickness for it.

[wavded]

Just ran into this today. Would be a great addition when you want an underline cursor but also have underline text so you can see it better. Here is an example from iTerm in Neovim where the cursor and the underlined text can be easily distinguished.