docs: update sidebar and documentation to include greg hooks registry

- Added new items to the sidebar for 'greg-hooks-and-events' and 'greg-hooks-registry' under the Framework and Reference categories, respectively.
- Enhanced the documentation layout by including references to the greg hooks registry in various guides and topics, improving accessibility to hook-related information.
- Updated descriptions in the documentation to clarify the purpose and usage of the greg hooks and their registry.

This commit aims to improve the visibility and usability of the greg hooks registry within the documentation.

docs/topics/index.md

@@ -16,7 +16,7 @@ Documentation is **curated** in this repository: guides, framework articles, ref
 |------|------------|
 | **Roles** | [By audience](/wiki/guides/players/audiences-overview) — [End users](/wiki/guides/players/overview), [Mod developers](/wiki/guides/mod-developers/overview), [Contributors (workflow)](/wiki/guides/contributors/topics-overview), [Sponsors](/wiki/guides/sponsors/overview) |
 | **Experience paths** | [Newbies](/wiki/audiences/newbies) · [Intermediates](/wiki/audiences/intermediates) · [Professionals](/wiki/audiences/professionals) |
-| **Technical reference** | [Reference & technical](/wiki/topics/reference/overview) |
+| **Technical reference** | [Reference & technical](/wiki/topics/reference/overview) — includes [greg IL2CPP hook registry](/wiki/reference/greg-hooks-registry) |
 | **Ship planning** | [Roadmap & planning](/wiki/topics/roadmap/overview) |
 | **Repository inventory** | [Repo inventory](/wiki/contributors/repo-inventory) |
 | **Steam, betas, backlog, game paths** | [Meta & operations](/wiki/topics/meta/overview) — [Game folder layout](/wiki/topics/meta/game-folder-layout) |