docs(theme-classic): fixed docs formatting issue for versions configu…

…ration of "docsVersionDropdown" navbar item

website/docs/api/themes/theme-configuration.mdx

@@ -597,7 +597,7 @@ Accepted fields:
 | `dropdownItemsAfter` | <code>[LinkLikeItem](#navbar-dropdown)[]</code> | `[]` | Add additional dropdown items at the end of the dropdown. |
 | `docsPluginId` | `string` | `'default'` | The ID of the docs plugin that the doc versioning belongs to. |
 | `dropdownActiveClassDisabled` | `boolean` | `false` | Do not add the link active class when browsing docs. |
-| `versions` | `string[] | object` | `undefined` | Specify a custom list of versions to include in the dropdown, or an object with more detailed version configurations. |
+| `versions` | <code>string[] \| object</code> | `undefined` | Specify a custom list of versions to include in the dropdown, or an object with more detailed version configurations. |
 
 ```mdx-code-block
 </APITable>