* Update annotations.md
A minor change to include the required fields when creating a new annotation via the annotations API. The error message when fields are missing is not descriptive and there is no indication in the current documentation (that I can see anyway) that would indicate these fields are required.
* Update annotations.md
Update required json body fields to only include fields that are actually required.
* Add required field in Swagger
Co-authored-by: Sofia Papagiannaki <1632407+papagian@users.noreply.github.com>
