Post History

Preview of edits so reviewers can see what has changed

Preview of edits so reviewers can see what has changed

When looking at a pending edit on the suggested edits page, only the markdown shows. There is no preview of how this will be rendered.

This presents two problems:
1. Any subtle error introduced by the edit that prevents the post from rendering correctly will be difficult to spot, risking a faulty edit being accepted
1. An edit that fixes a subtle error (perhaps by introducing a blank line), will look redundant to the edit reviewer, risking the fix being rejected

## Example

[By design, the `<details>` tag requires that markdown contained within it be separated from the surrounding HTML by a blank line](https://meta.codidact.com/posts/287279).

This means that the following two code blocks, that look near identical, render very differently.

### Without a blank line

```text
<details><summary>Summary</summary>
- details
- details
- details
</details>
```

renders as: (click on the arrow to expand and see the raw markdown has not been rendered)

<details><summary>Summary</summary>
- details
- details
- details
</details>

### With a blank line

```text
<details><summary>Summary</summary>

- details
- details
- details
</details>
```

renders as: (click on the arrow to expand and see the markdown has now been correctly rendered)

<details><summary>Summary</summary>

- details
- details
- details
</details>

## Real world occurrence

I'm raising this following suggesting an [edit that included fixing a `<details>` section](https://meta.codidact.com/posts/suggested-edit/979) where the first image does not render due to the lack of a blank line. If I hadn't also changed another part of the post in the same suggested edit, it would have looked redundant to any reviewer not familiar with this rare case of a blank line in HTML being relevant to the rendered result.