Fix #2495 - Add hyperlink support to :man
Fix #2495 - Add hyperlink support to :man

1. Add commands to navigate between man page links.
2. Add command to jump to a man page by following a man page link.
3. Add key map for <ret> to jump command.
4. Add key maps for a suggested user mode.

alexherbo2/kakoune,danr/kakoune,occivink/kakoune,alexherbo2/kakoune,alexherbo2/kakoune,occivink/kakoune,mawww/kakoune,Somasis/kakoune,occivink/kakoune,casimir/kakoune,lenormf/kakoune,casimir/kakoune,Somasis/kakoune,occivink/kakoune,jkonecny12/kakoune,danr/kakoune,alexherbo2/kakoune,jkonecny12/kakoune,lenormf/kakoune,Somasis/kakoune,mawww/kakoune,lenormf/kakoune,jkonecny12/kakoune,Somasis/kakoune,casimir/kakoune,danr/kakoune,jkonecny12/kakoune,mawww/kakoune,danr/kakoune,mawww/kakoune,casimir/kakoune,lenormf/kakoune