Search bar ignores `@` character

**Your Godot version:**
`4.7.stable`

**Issue description:**
The search bar in Godot Docs ignores the `@` character. This makes the `@GDScript` page buried under other GDScript-related pages in the search results.

Screenshots:

**URL to the documentation page:**
https://docs.godotengine.org/en/4.7/

Start at the Godot Docs search bar on the linked documentation site and reproduce the issue by searching for `@GDScript`, comparing the results with a search that includes the character. Done means the `@GDScript` page is no longer buried under unrelated GDScript results and the behavior is covered by a suitable check.

Written by the indexing model from the issue text.