Allow Void Response Body with Model Fields

[JamesChen-us]

fix #5070

[JamesChen-us]

@chrisradek @markcowl
When you have a moment, please take a look at this pr. I’d appreciate your feedback.

[chrisradek]

@JamesChen-us Thank you for your contribution!

I don't think we want to treat void as an empty schema object for 2 reasons:

1. An empty schema ({}) typically means anything would validate against it.
2. This causes the response content-type to be application/json, when really there shouldn't be any content type.

I think to support void in response contents, we could do something similar to what we did for request bodies: check if a response body is a voidType and ignore it if so. I did a quick test modifying this conditional to also check if data.body.type is void and get results that match when the @statusCode is omitted (except with the correct statusCode instead):

typespec/packages/openapi3/src/openapi.ts

Line 960 in a226a76

if (data.body === undefined) {

[JamesChen-us]

@chrisradek Thank you for clarifying the issue. I appreciate the feedback. Updated to skip content generation for void responses instead of creating empty schemas. Let me know if any adjustments are needed.