[DomCrawler] Changed typehints form DomNode to DomElement

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | only for people hacking the internal classes (which requires replacing the crawler too)
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #10924
| License       | MIT
| Doc PR        | n/a