Changes to Web Keyword Search

added the optional property reason to the response with the 200 status

added the optional property reason to the response with the 400 status

added the optional property reason to the response with the 401 status

added the optional property reason to the response with the 403 status

added the optional property reason to the response with the 429 status

added the optional property reason to the response with the 500 status

added the optional property reason to the response with the 503 status