Merge branch 'sg/rebase-progress' into maint

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