Use http_response.content_type when creating the response, or document that this field is not used in the conversion #252

The HttpResponse.content_type field is not being used when converting to aiohttp response. If the HttpResponse has a non-default content type, it won't be respected in the actual HTTP response. Consider using http_response.content_type when creating the response, or document that this field is not used in the conversion.

Originally posted by @Copilot in #221 (comment)