Merge branch 'js/for-each-ref-remote-name-and-ref'

The "--format=..." option "git for-each-ref" takes learned to show
the name of the 'remote' repository and the ref at the remote side
that is affected for 'upstream' and 'push' via "%(push:remotename)"
and friends.

* js/for-each-ref-remote-name-and-ref:
  for-each-ref: test :remotename and :remoteref
  for-each-ref: let upstream/push report the remote ref name
  for-each-ref: let upstream/push optionally report the remote name

This is the final iteration that made it into upstream Git's master
branch and that started out as 8148ee4 (Merge branch
'mingw/ref-filter-remote-name', 2017-10-29).

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho