rust wrong imports coloring

[RaafatTurki]

used:

not used:

it's like it took the green, dimmed it and applied it to the whole thing
something similar happens with multi import statements such as

they work great but when everything inside the curl braces is unused the curly braces themselves turn dim green

[0oAstro]

This feature probably requires a character by character dimming, which might slow down the neovim instance crazy when working on large projects.