Prompt Safari users to enable the extension on GitHub.com automatically #4220

Safari, unlike other browsers, treats the host permissions in the manifest as suggestions and they're not immediately enabled on install.

I think that, instead of the welcome tab, Safari users could be redirected to a local html page with a single button that enables it on both GitHub and Gist by browser.permission.requesting the manifest permissions. Once accepted the page could be redirected to the welcome tab as usual.

Contributors: You can implement this feature even if you don't use Safari. Browser detection can be added later.