doc: Fix malformed parameters in librados.h

Fixes parameters for rados_write_op_operate and rados_aio_write_op_operate

Fixes: #8661

Signed-off-by: Adam Crume <adamcrume@gmail.com>
Merge pull request #2023 from adamcrume/wip-8661

doc: Fix malformed parameters in librados.h

Reviewed-by: Sage Weil <sage@redhat.com>