people mastodon_url: use rel="me"

from "link verification" at https://docs.joinmastodon.org/user/profile/

If you put a link in your profile metadata, Mastodon checks if the linked page links back to your Mastodon profile. If so, you get a verification checkmark next to that link, since you are confirmed as the owner.

Behind the scenes, Mastodon checks for the rel="me" attribute on the link back. Likewise, Mastodon puts rel="me" on the links within profile metadata.

This scenario is slightly different since the person is not the owner of the torproject people page, but I think from context it's clear that this is verifying that the mastodon profile belongs to someone on the torproject people page.

Also update jnewsome's mastodon profile link.