fail to render simple type array in pdf and xlsx formats

[fugerit79]

When an array is of simple type, it is not correctly documented :

        testList2:
          description: Test list 3
          type: array
          items:
            type: string
            description: Array of string

POC :

openapi: 3.0.0
info:
  title: 'Sample Openapi Document'
  description: 'This is a sample yaml for yaml-doc-tool'
  version: '1.0.0'
servers:
  - url: http://localhost:8080/api
    description: Sample Development server
paths:
  /sample/id/{id}:
    get:
      summary: Sample
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: Ok
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SampleResult'
components:
  schemas:
    SampleResult:
      properties:
        id:
          type: string
          example: '1234'
          description: 'Id of the sample'
        sampleTest:
          type: string
          example: 'Sample text'
          description: 'Sample properties'
        sampleLevelTwoA:
          $ref: '#/components/schemas/SampleLevelTwoA'
        sampleLevelTwoB:
          $ref: '#/components/schemas/SampleLevelTwoB'
        sampleLevelTwoC:
          $ref: '#/components/schemas/SampleLevelTwoC'
        sampleLevelTwoD:
          $ref: '#/components/schemas/SampleLevelTwoD'
        sampleLevelTwoE:
          $ref: '#/components/schemas/SampleLevelTwoE'
    SampleLevelTwoA:
      properties:
        note:
          type: string
          example: 'Level two notes A'
          description: 'Level two description'
          minLength: 1
          maxLength: 5
        count:
          type: number
          example: 100
          description: 'Level two count'
          minimum: 0
          maximum: 99999
    SampleLevelTwoB:
      properties:
        note:
          type: string
          example: 'Level two notes B'
          description: 'Level two description'
    SampleLevelTwoC:
      properties:
        note:
          type: string
          example: 'Level two notes C'
          description: 'Level two description'
    SampleLevelTwoD:
      properties:
        note:
          type: string
          example: 'Level two notes D'
          description: 'Level two description'
    SampleLevelTwoE:
      properties:
        note:
          type: string
          example: 'Level two notes E'
          description: 'Level two description'
    SampleLevelTwoRef1:
      $ref: '#/components/schemas/SampleLevelTwoE'
    SampleLevelTwoRef2:
      $ref: '#/components/schemas/SampleLevelTwoD'
    SampleArrayString:
      description: Sample with array properties
      properties:
        testList1:
          description: Test list 1
          type: array
          items:
            $ref: '#/components/schemas/SampleLevelTwoA'
        testList2:
          description: Test list 3
          type: array
          items:
            type: string
            description: Array of string
        testList3:
          description: Test list 3
          type: array
          items:
            $ref: '#/components/schemas/SampleLevelTwoB'