Merge branch 'sg/rebase-progress'

Use "Erase in Line" CSI sequence that is already used in the editor
support to clear cruft in the progress output.

* sg/rebase-progress:
progress: use term_clear_line()
rebase: fix garbled progress display with '-x'
pager: add a helper function to clear the last line in the terminal
t3404: make the 'rebase.missingCommitsCheck=ignore' test more focused
t3404: modernize here doc style

diff --cc cache.h
Simple merge

diff --cc sequencer.c
Simple merge

diff --cc t/t3404-rebase-interactive.sh
Simple merge