Merge branch 'kh/name-rev-custom-format' into next

Merge branch 'kh/name-rev-custom-format' into next

A new builtin "git format-rev" is introduced for pretty formatting
one revision expression per line or commit object names found in
running text.

* kh/name-rev-custom-format:
  format-rev: introduce builtin for on-demand pretty formatting
  name-rev: make dedicated --annotate-stdin --name-only test
  name-rev: factor code for sharing with a new command
  name-rev: run clang-format before factoring code
  name-rev: wrap both blocks in braces