Merge branch 'mm/git-url-parse' into next

Merge branch 'mm/git-url-parse' into next

The internal URL parsing logic has been made accessible via a new
subcommand "git url-parse".

* mm/git-url-parse:
  t9904: add tests for the new url-parse builtin
  doc: describe the url-parse builtin
  builtin: create url-parse command
  urlmatch: define url_parse function
  url: return URL_SCHEME_UNKNOWN instead of dying
  url: move scheme detection to URL header/source
  url: move url_is_local_not_ssh to url.h
  connect: rename enum protocol to url_scheme