Rollup merge of #104415 - notriddle:notriddle/search-keyboard-commands, r=GuillaumeGomez

Rollup merge of #104415 - notriddle:notriddle/search-keyboard-commands, r=GuillaumeGomez

rustdoc: fix corner case in search keyboard commands

This fixes a bug when that shows up in nightly and in stable where:

* Search something
* Press down: first result is highlighted
* Press down: second result is highlighted
* Press down: third result is highlighted
* Press right: first result of second tab is highlighted
* Press left: third result of first tab is highlighted
* Press up: second result is highlighted
* Press up: first result is highlighted
* Press up: Search box is highlighted
* Press down: **third result** is highlighted, where it ought to highlight the first result