support for advaned formatting (squiggly underline?)

[colemickens]

As seen in the screenshot, alacritty renders some of my editor warnings with a yellow squiggly underline.

That's not present in rio, however. I assume this just isn't implemented yet?

[raphamorim]

Is not implemented yet in renderer level but implemented in ansi level, but that would be awesome to have. Saving as wishilist.

[raphamorim]

Adding more info on it: https://sw.kovidgoyal.net/kitty/underlines/

[raphamorim]

echo -e "\e[4:1mstraight underline\e[0m"
echo -e "\e[4:2mdouble underline\e[0m"
echo -e "\e[4:3mcurly underline\e[0m"
echo -e "\e[4:4mdotted underline\e[0m"
echo -e "\e[4:5mdashed underline\e[0m"