[REQ] Not able to exclude headers as parameters

Is your feature request related to a problem? Please describe.

We use the Kotlin-Retrofit-Coroutines to generate the sources based on the OpenApi specs. But in our manually generated code-base, we use for the headers OkHttp Interceptors, that way we don't have to supply in each call all the required headers.

But it does not seem to be a way to avoid generating those headers. We tried to download the Retrofit template and remove the {{>headerParams}} block: this ends up not adding the headers but it keeps all the "," for parameters separation:

Describe the solution you'd like

A way to avoid adding the header parameters to the generated endpoints

Describe alternatives you've considered

When manually removing {{>headerParams}} from the template it just works fine without keeping the "," leftovers

Start with modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-retrofit2/api.mustache and inspect how headerParams and parameter separators are rendered. Check the generated endpoint output when header parameters are excluded. Done means a supported way to omit those headers without leftover commas or invalid parameter lists.