Add a note to the annotations API document here https://www.elastic.co/guide/en/kibana/7.8/apm-api.html and https://www.elastic.co/guide/en/kibana/7.8/apm-annotation-api.html#apm-annotation-api that specifically calls out that a user will have to use CURL command or an API tool to call these APIs.

Lets also call out that Kibana developer tools cannot be used to call these APIs.