Merge branch 'es/worktree-add-cleanup'

Merge branch 'es/worktree-add-cleanup'

The "new-worktree-mode" hack in "checkout" that was added in
nd/multiple-work-trees topic has been removed by updating the
implementation of new "worktree add".

* es/worktree-add-cleanup: (25 commits)
  Documentation/git-worktree: fix duplicated 'from'
  Documentation/config: mention "now" and "never" for 'expire' settings
  Documentation/git-worktree: fix broken 'linkgit' invocation
  checkout: drop intimate knowledge of newly created worktree
  worktree: populate via "git reset --hard" rather than "git checkout"
  worktree: avoid resolving HEAD unnecessarily
  worktree: make setup of new HEAD distinct from worktree population
  worktree: detect branch-name/detached and error conditions locally
  worktree: add_worktree: construct worktree-population command locally
  worktree: elucidate environment variables intended for child processes
  worktree: make branch creation distinct from worktree population
  worktree: add: suppress auto-vivication with --detach and no <branch>
  worktree: make --detach mutually exclusive with -b/-B
  worktree: introduce options container
  worktree: simplify new branch (-b/-B) option checking
  worktree: improve worktree setup message
  branch: publish die_if_checked_out()
  checkout: teach check_linked_checkout() about symbolic link HEAD
  checkout: check_linked_checkout: simplify symref parsing
  checkout: check_linked_checkout: improve "already checked out" aesthetic
  ...