Auto merge of #18349 - dqkqd:issue-18344, r=Veykril

feat: render docs from aliased type when type has no docs

Trying to close #18344

- [x] ~Find the docs by traversing upwards if the type itself has none but aliasing for another type that might have.~
- [x] Show docs from aliased type.
- [x] Showing description that we are displaying documentation for different definition in hover box.

![image](https://github.com/user-attachments/assets/820d6f97-aa2c-4dc4-8a25-75746e32d950)

Author: bors