Merge branch 'maint-1.8.1' into maint

Merge branch 'maint-1.8.1' into maint

* maint-1.8.1:
  bundle: Add colons to list headings in "verify"
  bundle: Fix "verify" output if history is complete
  Documentation: filter-branch env-filter example
  git-filter-branch.txt: clarify ident variables usage
  git-compat-util.h: Provide missing netdb.h definitions
  describe: Document --match pattern format
  Documentation/githooks: Explain pre-rebase parameters
  update-index: list supported idx versions and their features
  diff-options: unconfuse description of --color
  read-cache.c: use INDEX_FORMAT_{LB,UB} in verify_hdr()
  index-format.txt: mention of v4 is missing in some places