[skip ci] fix syntax in CODEOWNERS

• Fix invalid usernames
  • Fix spelling of ngie-eign
  • Delete users who aren't members of the FreeBSD org
• Fix spelling of usr.bin/fetch in CODEOWNERS
• rm "a directory anywhere in the repo" patterns from CODEOWNERS Even though they're documented as working, in practice they don't. https://docs.github.com/en/github/creating-cloning-and-archiving-repositories/creating-a-repository-on-github/about-code-owners#codeowners-file-location

MFC after: 2 weeks
Sponsored by: Axcient
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D30849