Merge branch 'jc/request-pull-show-head-4'

Merge branch 'jc/request-pull-show-head-4'

* jc/request-pull-show-head-4:
  request-pull: use the annotated tag contents
  fmt-merge-msg.c: Fix an "dubious one-bit signed bitfield" sparse error
  environment.c: Fix an sparse "symbol not declared" warning
  builtin/log.c: Fix an "Using plain integer as NULL pointer" warning
  fmt-merge-msg: use branch.$name.description
  request-pull: use the branch description
  request-pull: state what commit to expect
  request-pull: modernize style
  branch: teach --edit-description option
  format-patch: use branch description in cover letter
  branch: add read_branch_desc() helper function

Conflicts:
	builtin/branch.c