Unused interface definition in HandleLinkPressFeature.ts example

In the [HandleLinkPressFeature.ts example](https://formidable-webview.github.io/webshell/docs/implementing-features#building-a-feature-class) for building a Feature Class, the `LinkPressOptions` interface is defined but never used.

```typescript
export interface LinkPressOptions {
  preventDefault?: boolean;
}
```