Merge branch 'en/pull-do-not-rebase-after-fast-forwarding'

"git pull --rebase" tried to run a rebase even after noticing that
the pull results in a fast-forward and no rebase is needed nor
sensible, for the past few years due to a mistake nobody noticed.

* en/pull-do-not-rebase-after-fast-forwarding:
  pull: avoid running both merge and rebase

diff --cc builtin/pull.c
Simple merge