Fixed tripcode encoding

[45ytjfgdu745754745745]

Pull Requests 4 Kokonotsuba

• [X] In the case that it is a fix: Highlights what issue the pull request is fixing
  • Fixed tripcode encoding in koko.php
• [X] Summarises what the changes will do
  • Fixed tripcode encoding
• [X] Has been tested, preferably with this parameters
  • Debian 10
  • nginx
  • MariaDB
  • PHP 7.3
  • If you're unable to, just test it on your system, as in most cases it will work on Heyuri too

[kaguy4]

Thanks!