Do not list one-line descriptions from the actual commits being
merged.
---summary,--no-summary::
+--summary::
+--no-summary::
Synonyms to --log and --no-log; these are deprecated and will be
removed in the future.
---file <file>, -F <file>::
+-F <file>::
+--file <file>::
Take the list of merged objects from <file> instead of
stdin.