Merge branch 'master' of github.com:git/git

Merge branch 'master' of github.com:git/git

* 'master' of github.com:git/git: (397 commits)
  Git 2.33-rc0
  The seventh batch
  ci/install-dependencies: handle "sparse" job package installs
  ci: run "apt-get update" before "apt-get install"
  cache-tree: prefetch in partial clone read-tree
  unpack-trees: refactor prefetching code
  pack-bitmap: check pack validity when opening bitmap
  bundle tests: use test_cmp instead of grep
  bundle tests: use ">file" not ": >file"
  The sixth batch
  doc: pull: fix rebase=false documentation
  pack-bitmap: clarify comment in filter_bitmap_exclude_type()
  doc: clarify description of 'submodule.recurse'
  doc/git-config: simplify "override" advice for FILES section
  doc/git-config: clarify GIT_CONFIG environment variable
  doc/git-config: explain --file instead of referring to GIT_CONFIG
  t0000: fix test if run with TEST_OUTPUT_DIRECTORY
  multi-pack-index: fix potential segfault without sub-command
  refs/debug: quote prefix
  t0000: clear GIT_SKIP_TESTS before running sub-tests
  ...