Add comments_count to example json responses in calendar_events

calendar_events json response now returns the comment count. Updates
the example json responses accordingly.
Merge branch 'update-docs-with-comments_count-on-calendar_events'
Add `app_url` to json responses in documentation
Merge branch 'add-app_url-to-json-responses-docs'
Add API docs explaining how to get list of projects user has access to
Merge branch 'app-project-per-person-docs'
Fix docs to mention project access
Merge branch 'api-fix-documentation-for-projects-per-person'
Add completed todos and todos index to API docs
Fix incorrect todo json response

The json response for individual todos didn't match what was actually
returned.
Fix commas :grin:
Merge branch 'add-completed-todos-to-api-docs'
Merge branch 'master' into archiving-discussions

Conflicts:
	sections/topics.md