docs: link pgvector extension to ai guide

apps/docs/pages/guides/database/extensions/pgvector.mdx

@@ -9,6 +9,8 @@ export const meta = {
 
 [pgvector](https://github.com/pgvector/pgvector/) is a PostgreSQL extension for vector similarity search. It can also be used for storing [embeddings](https://supabase.com/blog/openai-embeddings-postgres-vector).
 
+Learn more about Supabase's [AI & Vector](/docs/guides/ai) offering.
+
 ## Concepts
 
 ### Vector similarity