Add a charcatere to a way to show wich line is select on menu

[Wateir]

Body

What are you proposing?

Currently the only way to know which line is select on menu on zed is by color, the one select have a different background, i want another way for people like me who use theme who have the same color everywhere

Why does this matter?

It's not possible here to know what is the choice i'm gonna make

If zed expose a settings to put a char to show wich line is select it's possible to know (see my little photshop thingy)

Possible approach

I don't know at all rust and don't have read the codebase, so now, i can vibecode some PR if need, but i thing someone way better can do it