man/io_uring_buf_ring_add.3: fix function signature
The return type is void, not int.
@@ -9,7 +9,7 @@ io_uring_buf_ring_add \- add buffers to a shared buffer ring
.nf
.B #include <liburing.h>
.PP
-.BI "int io_uring_buf_ring_add(struct io_uring_buf_ring *" br ",
+.BI "void io_uring_buf_ring_add(struct io_uring_buf_ring *" br ",
.BI " void *" addr ",
.BI " unsigned int " len ",
.BI " unsigned short " bid ",
