[AP] Use contact.alias if it exists instead of contact.url for mention links
[AP] Use contact.alias if it exists instead of contact.url for mention links

- Make mentions links handled by Mastodon for logged in users

friendica/friendica,friendica/friendica,tobiasd/friendica,annando/friendica,tobiasd/friendica,fabrixxm/friendica,friendica/friendica,tobiasd/friendica,fabrixxm/friendica,tobiasd/friendica,fabrixxm/friendica,tobiasd/friendica,annando/friendica,fabrixxm/friendica,annando/friendica,friendica/friendica,annando/friendica,annando/friendica,fabrixxm/friendica,friendica/friendica