Rename ffi io_uring_prep_sock_cmd _> io_uring_prep_cmd_sock()

The non-ffi versions already use this name, and to make this as painless
as it can be, rename the ffi version even though it is technically
the better one. The documentation also matches prep_cmd_sock().

Link: #1013
Fixes: 2459fef ("io_uring_prep_cmd: Create a new helper for command ops")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

src/liburing-ffi.map

@@ -179,7 +179,7 @@ LIBURING_2.4 {
 LIBURING_2.5 {
 	global:
 		io_uring_queue_init_mem;
-		io_uring_prep_sock_cmd;
+		io_uring_prep_cmd_sock;
 		io_uring_prep_read_multishot;
 		io_uring_prep_waitid;
 		io_uring_prep_futex_wake;