### What?
- fixes HTML nodes placement for inline previews
- (breaking?) disallows file previews in headings (`<h1>`, …), striked out (`<del>`), `<summary>` and other environments
- allows them in `<span>`, `<em>` and `<strong>` environments, but without extra formatting
- allows them in `<div>`, `<li>`, `<th>`, `<td>` and `<details>` (not in `<summary>`) environments following the parent’s formatting
- improves overall HTML validity, but only to the extend of the direct parent nodes (but not a big issue, as modern browsers tend to ignore invalid HTML and still parse it)
- fix#9136
See examples of strangely formatted file previews at https://v13.next.forgejo.org/mahlzahn/test/issues/4.
### How is it implemented?
For links in `<p>`, `<span>`, `<em>` and `<strong>` parent nodes it inserts the file preview and following text as siblings to the **parent** node.
`<em>before LINK after</em>`
→ `<em>before </em>PREVIEW<em> after</em>`
For links in `<div>`, `<li>`, `<th>`, `<td>` and `<details>` parent nodes it inserts the file preview and following text as siblings to the **text** node.
`<div>before LINK after</div>`
→ `<div>before PREVIEW after</div>`
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/9181
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: Robert Wolff <mahlzahn@posteo.de>
Co-committed-by: Robert Wolff <mahlzahn@posteo.de>
14c5462019