Merge branch 'jc/maint-fmt-merge-msg-no-edit-lose-credit' into maint

"git merge --no-edit" computed who were involved in the work done
on the side branch, even though that information is to be discarded
without getting seen in the editor.

* jc/maint-fmt-merge-msg-no-edit-lose-credit:
  merge --no-edit: do not credit people involved in the side branch

diff --cc builtin.h
Simple merge

diff --cc builtin/fmt-merge-msg.c
Simple merge

diff --cc builtin/merge.c
Simple merge