[Swift4] --reserved-words-mappings does not work for model names

Description

I'm try to generate code from spec using this command:

swagger-codegen generate -l swift4 -i receipt-details.json -o "_" --reserved-words-mappings "Error=ErrorModel"

Spec has model:

        "Error": {
            "type": "object",
            "properties": {
                "code": {
                    "type": "integer",
                    "format": "int32"
                },
                "message": {
                    "type": "string"
                }
            }
        }

This results in a error:

[main] WARN io.swagger.codegen.DefaultCodegen - Error (reserved word) cannot be used as model name. Renamed to ModelError

Swagger-codegen version

2.3.1

Swagger declaration file content or url

Definitions part:

    "definitions": {
        "Error": {
            "type": "object",
            "properties": {
                "code": {
                    "type": "integer",
                    "format": "int32"
                },
                "message": {
                    "type": "string"
                }
            }
        }
    }

Command line used for generation

swagger-codegen generate -l swift4 -i receipt-details.json -o "_" --reserved-words-mappings "Error=ErrorModel"

Steps to reproduce

Run following command for swagger spec containing model with name Error:

swagger-codegen generate -l swift4 -i receipt-details.json -o "_" --reserved-words-mappings "Error=ErrorModel"

Suggest a fix/enhancement

--reserved-words-mappings should work for model names too.

Start with the DefaultCodegen reserved-word handling used by the Swift4 generator and reproduce the documented swagger-codegen command with a model named Error. Verify that --reserved-words-mappings changes the generated model name to ErrorModel instead of ModelError.