Merge branch 'dd/git-bisect-builtin'

`git bisect` becomes a builtin.

* dd/git-bisect-builtin:
  bisect; remove unused "git-bisect.sh" and ".gitignore" entry
  Turn `git bisect` into a full built-in
  bisect--helper: log: allow arbitrary number of arguments
  bisect--helper: handle states directly
  bisect--helper: emit usage for "git bisect"
  bisect test: test exit codes on bad usage
  bisect--helper: identify as bisect when report error
  bisect-run: verify_good: account for non-negative exit status
  bisect run: keep some of the post-v2.30.0 output
  bisect: fix output regressions in v2.30.0
  bisect: refactor bisect_run() to match CodingGuidelines
  bisect tests: test for v2.30.0 "bisect run" regressions

diff --cc .gitignore
Simple merge

diff --cc Makefile
Simple merge

diff --cc git.c
Simple merge