development.7: Remove CVS and SVN cross-references

Instead, point to the homepages of the projects.

MFC after:	1 week

share/man/man7/development.7

@@ -23,7 +23,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 1, 2021
+.Dd July 21, 2022
 .Dt DEVELOPMENT 7
 .Os
 .Sh NAME
@@ -195,9 +195,9 @@ December 2002.
 It was since extensively modified by
 .An Eitan Adler Aq Mt eadler@FreeBSD.org
 to reflect the repository conversion from
-.Xr cvs 1
+.Lk https://www.nongnu.org/cvs/ CVS
 to
-.Xr svn 1 .
+.Lk https://subversion.apache.org/ Subversion .
 It was rewritten from scratch by
 .An Edward Tomasz Napierala Aq Mt trasz@FreeBSD.org
 for