man/io_uring_enter.2: add new 5.15 opcodes
man/io_uring_enter.2: add new 5.15 opcodes

This documents:

IORING_OP_MKDIRAT, IORING_OP_SYMLINKAT, and IORING_OP_LINKAT.

Signed-off-by: Jens Axboe <cd8c6775e60d6f67a6984377324e5290df3d5358@kernel.dk>

axboe/liburing,axboe/liburing,axboe/liburing