- fix svn command and mention svnweb interface

PR:		195295 (based on)
Differential Revision:	https://reviews.freebsd.org/D1222
Submitted by:	pt307@cam.ac.uk
Approved by:	wblock (mentor)


git-svn-id: svn+ssh://svn.freebsd.org/doc/head@46040 c2e8774f-c49f-e111-b436-862b2bbc8956