Now that ResourceLoader's CodexModule class supports basic code splitting, we should deprecate the codex-search and codex-search-styles RL modules so that we can eventually remove them.
However, in order to do that, we should make sure that the Codex page on MediaWiki includes some clear instructions for how to use code-splitting (in both CSS-only or CSS and JS features). The deprecation notice we add in RL could point directly to the appropriate section of this page.
Acceptance Criteria
- Update the https://www.mediawiki.org/wiki/Codex page to include clear instructions/examples on how to use code splitting
- Add a deprecated line in RL for codex-search and codex-search-styles