Merge branch 'maint'

Merge branch 'maint'

* maint:
  gitweb: clarify search results page when no matching commit found
  Documentation: add a FILES section for show-ref
  Makefile: add missing dependency on http.h
  Makefile: add missing dependencies on url.h
  Documentation/git-log: Clarify --full-diff
  git-rebase: fix typo when parsing --force-rebase
  imap-send: Fix sprintf usage
  prune: allow --dry-run for -n and --verbose for -v
  notes: allow --dry-run for -n and --verbose for -v
  Document -B<n>[/<m>], -M<n> and -C<n> variants of -B, -M and -C
  Documentation: cite git-am from git-apply
  t7003: fix subdirectory-filter test
  Allow "check-ref-format --branch" from subdirectory
  check-ref-format: handle subcommands in separate functions
  pretty-options.txt: match --format's documentation with implementation.