Terminology fix: "Mime type" -> "Media type"
Terminology fix: "Mime type" -> "Media type"

this PR changes the anchor #mimeType to #mediaType, so if there are external links to this anchor, then those should be updated as well. alternatively, we could add a second anchor, effectively aliasing the section to be addressable by both identifiers.
OAI/OpenAPI-Specification,OAI/OpenAPI-Specification,OAI/OpenAPI-Specification