Release Notes:

- N/A

---

Fix this long-standing issue so that we can support Link hover colors.

And renamed `text_layout` example to `text_style`.

---

I spent some time studying the process of this text style change and
found it a bit complicated.

At first, I thought there was a problem with refine and it was not
passed properly. After changing it, I found that it was not the problem.

Then I found that it was because `TextRun` had already stored the
`color`, `background`, `underline`, `strikethrough` in TextRun in the
`request_layout` stage. They area calculate at the `request_layout`
stage, but request_layout stage there was no `hitbox`, so the hover
state was not obtained.

```bash
cargo run -p gpui --example text_style
```


https://github.com/user-attachments/assets/24f88f73-775e-41d3-a502-75a7a39ac82b

---------

Co-authored-by: Mikayla Maki <mikayla.c.maki@gmail.com>