OpenAPI: Set properties of objects nested in arrays

[Floppy012]

When generating the documentation, the OpenAPI does not include properties of objects that are nested in arrays. This PR aims at fixing this bug.

Before:

openapi: 3.0.3
info:
  title: 'Test'
  version: 1.0.0
paths:
  /api/test:
    get:
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                example:
                  someArray:
                    - anotherObjectKey: objectValue
                properties:
                  someArray:
                    type: array
                    example:
                      anotherObjectKey: objectValue
                    items:
                      type: object

After:

openapi: 3.0.3
info:
  title: 'Test'
  version: 1.0.0
paths:
  /api/test:
    get:
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: object
                example:
                  someArray:
                    - anotherObjectKey: objectValue
                properties:
                  someArray:
                    type: array
                    example:
                      anotherObjectKey: objectValue
                    items:
                      type: object
                      properties:
                        anotherObjectKey:
                          type: string
                          example: objectValue

Diff:

--- a/before
+++ b/after
@@ -22,3 +22,7 @@ paths:
                       anotherObjectKey: objectValue
                     items:
                       type: object
+                      properties:
+                        anotherObjectKey:
+                          type: string
+                          example: objectValue