bubblewrap manpage is desynced from source code

i decided to study the `--bind-fd` flag and brought up the manpage. however, it wasn't there. but i knew it must be somewhere because i've seen it before. i checked the repo, and in the source code it mentions it. in fact, it mentions it from `--help`. so, it appears the manpage got desynced from the sourced code. is this on purpose? if not i can create a patch.