Update Mastodon API documentation
Update Mastodon API documentation

- Change endpoint label style to monospace
- Explicit expected IDs for follow_requests endpoints
- Add official documentation link for api/v1/instance/peers
- Add unimplemented endpoint api/v1/instance/activity

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