[Feature Req] --listen allow unix domain sockets

[notklea]

I propose that fzf --listen allow giving it a path to a UDS address instead of doing network request doing requests via uds, i hope i made my request clear.

Thank in advance

[junegunn]

I'm on it. #4541

[junegunn]

Implemented in 01cb38a. It's pretty basic, so please let me know if it doesn't work as expected or needs some changes.