Update search index registration in the plugin documentation #21709
Description
Change Type
Correction
Area
Plugins
Proposed Changes
The plugin documentation currently shows registering search indexes with an indexes = [...] list in search.py, while the general search documentation uses @register_search on the SearchIndex class.
Since @register_search is the preferred approach going forward, the plugin documentation should be updated to reflect that. This would keep the examples consistent and make the recommended pattern clearer for plugin authors.