Inner class with reserved kotlin name is broken on kotlin-server generated files

There's a bug generating kotlin-server reserved property types when combined with inner types of data classes (maybe wider)

With build.gradle:

def generatedSources = "src/main/openapi"

openApiGenerate {
    generatorName = "kotlin-server"
    inputSpec = "$projectDir/open-api/LoanAccounts.yaml".toString()
    outputDir = "$projectDir".toString()
    apiPackage = "net.satago.mambu.client.api.clients"
    modelPackage = "net.satago.mambu.client.api.models"
    globalProperties = [
            models: "",
            apis  : "",
    ]
    configOptions = [
            sourceFolder      : generatedSources,
            dateLibrary       : "java8",
            enumPropertyNaming: "original",
            interfaceOnly     : "true",
            library           : "jaxrs-spec",
    ]
}

Instead of generating:

data class FilterCriteria {
    val `field`: FilterCriteria.`Field`

    enum class `Field` {
        ...
    }
}

generates quotes URL-encoded:

data class FilterCriteria {
    val `field`: FilterCriteria.`Field`

    enum class `Field` {
        ...
    }
}

Using openapi-generator-5.4.0

Start with build.gradle, the openapiGenerate configuration, and the generated Kotlin files from open-api/LoanAccounts.yaml. Compare the expected FilterCriteria output with the generated URL-encoded reference, then verify that the kotlin-server output preserves valid Kotlin backtick quoting for the inner Field type.