svn: change log messages

Fixing mistakes in SVN log messages isn't something it offers right out of the box.

As an admin you can change any log message you want:

svnadmin setlog --bypass-hooks c:/svn/myrepo -r 1234 1234-new-log-msg.txt


As a regular user your admin has to setup certain things so you can do it. Full details are on the SVN faq.