swapon.2: correct FreeBSD release that introduced swapoff

emaste · emaste · commit d52a5a3491a7 · 2023-09-21T12:53:50.000-04:00
It was introduced in 92da00b, after 5.0 and beforen 5.1. Reported in ziglang/zig#16590. (cherry picked from commit b15f640) (cherry picked from commit f4bb052)
diff --git a/lib/libc/sys/swapon.2 b/lib/libc/sys/swapon.2
@@ -158,4 +158,4 @@ system call appeared in
 The
 .Fn swapoff
 system call appeared in
-.Fx 5.0 .
+.Fx 5.1 .
