closes bpo-43349: Fix tuning(7) manpage hyperlink. (GH-24680)

diff --git a/Doc/library/resource.rst b/Doc/library/resource.rst
index 00ff3b5..67e9b44 100644
--- a/Doc/library/resource.rst
+++ b/Doc/library/resource.rst
@@ -241,7 +241,9 @@
    The maximum size (in bytes) of the swap space that may be reserved or
    used by all of this user id's processes.
    This limit is enforced only if bit 1 of the vm.overcommit sysctl is set.
-   Please see :manpage:`tuning(7)` for a complete description of this sysctl.
+   Please see
+   `tuning(7) <https://www.freebsd.org/cgi/man.cgi?query=tuning&sektion=7>`__
+   for a complete description of this sysctl.
 
    .. availability:: FreeBSD 9 or later.