[BUG][MARKDOWN] Enums in model are empty

Description

Enums in a model do not show possible values; they just have an empty table like regular objects, which is not suitable here.

components:
  schemas:
    WarningType:
      enum:
        - FORMATTED
        - DISCONTINUITY
        - SWITCH

# WarningType
## Properties

Name | Type | Description | Notes
------------ | ------------- | ------------- | -------------

[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)

openapi-generator version

4.3.0

OpenAPI declaration file content or url

bug.zip

Command line used for generation

<groupId>org.openapitools</groupId>
<artifactId>openapi-generator-maven-plugin</artifactId>
<version>4.3.0</version>
<executions>
  <execution>
    <id>markdown</id>

mvn clean compile

Steps to reproduce

Create OpenAPI yaml with enum component.

Related issues/PRs

Suggest a fix

Reproduce the issue from the attached bug.zip using the shown OpenAPI Generator Maven setup and inspect the generated Markdown model for WarningType. Compare enum output with the empty Properties table and verify that generated enum models list their possible values without affecting regular object models.