Merge branch 'mt/add-rm-in-sparse-checkout'

Merge branch 'mt/add-rm-in-sparse-checkout'

"git add" and "git rm" learned not to touch those paths that are
outside of sparse checkout.

* mt/add-rm-in-sparse-checkout:
  rm: honor sparse checkout patterns
  add: warn when asked to update SKIP_WORKTREE entries
  refresh_index(): add flag to ignore SKIP_WORKTREE entries
  pathspec: allow to ignore SKIP_WORKTREE entries on index matching
  add: make --chmod and --renormalize honor sparse checkouts
  t3705: add tests for `git add` in sparse checkouts
  add: include magic part of pathspec on --refresh error