Color of "default" Response

[dolmen]

In operations, the default response in a Responses object is often used to specify generic responses such as error cases (because it can be very tedious to document every possible status returned, and a bit of doc is better than nothing). Currently default is always rendered in green.

I propose that default would be rendered using a color (well, CSS class) depending on the presence of other responses in the same Responses object:

• if at least one response in the 100-399 range is specified, render default in red
• if none 100-399 status is specified, render default in green

For an example of spec where default is used to specifiy generic error messages and which is incorrectly always rendered in green with ReDoc: http://developers.ijenko.com/swagger.json