Improve the coreutils manpage

[sylvestre]

issues:

• show coreutils-coreutils
• in random order

see https://manpages.debian.org/unstable/rust-coreutils/rust-coreutils.1.en.html

[cakebaker]

All hashsum utils (b2sum, sha1sum, etc) are listed between coreutils-hashsum and coreutils-head, is this the expected behavior? And there is also a coreutils-help listed at the end of the list.

[sylvestre]

More or less, yes. Because it is the name of the uu function. On the user perspective, I can fix that.

It is the same for test and [

I would prefer do that in a different PR after this one merges