Rollup merge of #142497 - GuillaumeGomez:fix-random-search-failure, r=lolbinarycat

Fix random failure when JS code is executed when the whole file was not read yet

Very randomly (and rarely), when I arrived on a page with `?search=something` in the URL, I got this error:

![Screenshot From 2025-06-14 11-27-46](https://github.com/user-attachments/assets/4b61b067-4e80-49c1-9a45-cff1509bf86a)

Moving the `initSearch` function at the bottom to ensure everything has been loaded fixes the issue.

PS: Sorry for the noise. Pushed to the wrong branch and rust-lang/rust#142496 closed. ><

Author: tgross35