`response_body` should be text if the content-type is text-like

`response_body` should be text, and not a blob, when the `Content-type` mimetype is:

- has a type of `text`, ex `text/plain`, `text/html`, etc.
- Special case `application/json`
- Special case `application/xml`

maybe some others

https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types