After donating to Tor, the thank-you page contains some CTAs which imply you...

After donating to Tor, the thank-you page contains some CTAs which imply you can click them to post to social media about your donation. The initial commit to this MR addresses the first of these two CTAs - clicking on the Twitter button will bring you to x.com (nee Twitter) and - if you're logged in - pre-fill a tweet composition window with relevant copy and a link back to the Tor donate page.

A secondary commit addresses the other, the Mastodon CTA. A snippet of JS similar to the one in use elsewhere in the Tor ecosystem prompts the user for their Mastodon instance when the CTA is clicked, then behaves similarly to the x.com CTA (except with the user's own Mastodon instance).