-l html does not handle $ref to simple string schema

Description

The attached swagger.yaml defines a schema named stringOption which is type string with an enum.
The other schema context uses it.
In the output for -l html the enum values are not presented/rendered.

Swagger-codegen version

2.2.3-SNAPSHOT

Swagger declaration file content or url

swagger: '2.0'
info:
  version: '1'
  title: swagger-codegen-string-ref-issue
  description: a $ref to a string schema is not rendered correctly for -i html
paths:
  /contexts:
    post:
      summary: Create a context
      description: Create a context.
      operationId: createContext
      consumes:
        - application/json
      produces:
        - application/json
      parameters:
      - name: body
        in: body
        description: Context definition
        required: true
        schema:
          $ref: '#/definitions/context'
      responses:
        '201':
          description: Context created
          schema:
            $ref: '#/definitions/context'
definitions:
  context:
    type: object
    required:
      - stringOption
      - name
    properties:
      name:
        description: The context name
        type: string
      stringOption:
        $ref: '#/definitions/stringOption'
  stringOption:
    description: The context launch type
    type: string
    enum:
      - valueA
      - valueB
    default: valueB
    example: valueA

Command line used for generation

java -jar swagger-codegen-cli.jar generate -l html -o /tmp -i ref-string-schema.yaml

Steps to reproduce

run swagger-codegen ; view /tmp/index.html

See attached index.html output

Related issues/PRs

Suggest a fix/enhancement

Start by running swagger-codegen-cli.jar with the provided ref-string-schema.yaml and inspect the generated /tmp/index.html. Trace the HTML generation path for the referenced stringOption schema; done means the enum values valueA and valueB are rendered in the output.