KeePassXC User Guide can't open because of Tor Browser's AppArmor confinement

In KeePassXC, if a user tries to open the User Guide from the Help menu, the user will receive in Tor Browser the error message: "Hmm. We’re having trouble finding that site." It seems Tor Browser is trying to load the User Guide from a nonexistent server, usr. I believe Tor Browser is doing this because there's no leading forward slash in the URL to the User Guide.

If a leading forward slash is inserted in the URL, taking the user to file:///usr/share/keepassxc/docs/KeePassXC_UserGuide.html, the user will receive the error message: "Access to the file was denied." AFAIK, this is because of Tor Browser's AppArmor confinement.

NB: Allowing Tor Browser to open HTML documentation was discussed previously in #16432 (closed).