- point to correct url, as this does not resolve

PR:		195714
Differential Revision:	https://reviews.freebsd.org/D1270
Submitted by:	pt307@cam.ac.uk
Approved by:	bcr (mentor)


git-svn-id: svn+ssh://svn.freebsd.org/doc/head@46073 c2e8774f-c49f-e111-b436-862b2bbc8956