Update "How to Report a Bug or Give Feedback" to reflect GitLab migration

We need to update this entry:

Trac

You can file a ticket at https://trac.torproject.org. We track all Tor Browser 9 related issues with the tbb-9.0-issues keyword. Tickets related to our website should be added with the component "Webpages/Website."

https://support.torproject.org/misc/bug-or-feedback/