Atril 1.26.2 - renaming Bookmark with char & cause using above bookmark name

In Atril 1.26.2

## Reproduce

1. Menu Bookmarks > Add Bookmark
2. Side pane > show Bookmark pane
3. click on the bookmark for rename, input have to contain `&` (like in `R&D`) 
4. `Enter` --> entered text is replaced by the text of the upper bookmark

<img width="742" height="462" alt="Image" src="https://github.com/user-attachments/assets/14d7f01d-cd7d-4380-b889-27364cc9a378" />

