block: lift bio_is_zone_append to bio.h

Make bio_is_zone_append globally available, because file systems need
to use to check for a zone append bio in their end_io handlers to deal
with the block layer emulation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241104062647.91160-4-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>