Add documentation for sequence.format

index e61775e..76f0a4d 100644
@@ -555,6 +555,15 @@ sequence.editor::
 	It can be overridden by the `GIT_SEQUENCE_EDITOR` environment variable.
 	When not configured the default commit message editor is used instead.
 
+sequence.format::
+	Format of commit table generated by `git rebase -i` for rebase
+	instruction file. It can be overridden by the
+	`GIT_SEQUENCE_FORMAT` environment variable. When not
+	configured the default `oneline` format is used instead. NOTE:
+	Because the second column must be the hash, you may omit this
+	in the format string and it will be inserted. Formats must be
+	one line.
+
 core.pager::
 	Text viewer for use by Git commands (e.g., 'less').  The value
 	is meant to be interpreted by the shell.  The order of preference