[dev] dmenu : autoconfirm pull request

Hello, here is a small pull request for dmenu,
I'm not a developper, I've essentially bound together
and rearranged hints that Donald Chai gave me on the discord server.

Can someone have a look at it and give feedback,
I'm either not a native english speaker, the man page may contain
non correct english text.

Thanks to Suckless for providing softwares that give
pleasure to work with and make novices curious about code.