List available representations in 406 body

[brackendawson]

Becasue RFC7231 says we should.

fixes #434

[brackendawson]

I chose to not remove duplicates from available because this is the last thing in detectRoute() and therefore there should be none?

[brackendawson]

Also was this supposed to test a 406 response?

go-restful/web_service_test.go

Line 154 in 8487208

func TestContentType406PlainJson(t *testing.T) {

[emicklei]

I chose to not remove duplicates from available because this is the last thing in detectRoute() and therefore there should be none?

please explain why not removing dups?

[brackendawson]

please explain why not removing dups?

Because the Accept header is the last thing checked in the router, a valid path should not contain any duplicate media types. If it did then a matching call would fail.

It does look like the sort of thing that would get missed if another switch was added to the router after Accept. I can add deduplication if you like? It is only exposed in the error case.