Fix doc typo.
Fix doc typo.

Suggested by: S. Ramaswamy <ramaswamy@collab.net>

* doc/user/svn-best-practices.html: It's "may" not "main".

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion