content: improve components docs for the alignment property

### URL

https://ionicframework.com/docs/api/

### Issue Description

The following components have the `alignment` property documented at these links:
- [Checkbox](https://ionicframework.com/docs/api/checkbox#alignment)
- [Radio](https://ionicframework.com/docs/api/radio#alignment)
- [Toggle](https://ionicframework.com/docs/api/toggle#alignment)

The playground examples currently only demonstrate how the `alignment` property works horizontally when the label placement is set to `stacked`. However, they do not show how the `alignment` property affects vertical alignment with the `fixed`, `start`, and `end` label placements.

We should add examples demonstrating how `alignment` works vertically, similar to the following, for each component:

```html

```

> [!NOTE]
> This is just one example of how to illustrate the usage. It doesn't have to be exactly like the example provided.