docs: pass the source positionally in the TypeScript view example

`createMaterializedView` takes the source table name as its second
argument and the options after it, both in the SDK this was written
against and in main. The example passed `source` inside the options
object instead. It is not an executed example; the signature comes from
nodejs/lancedb/connection.ts.

docs/web/management/materialized-view.mdx

@@ -33,8 +33,7 @@ view = db.create_materialized_view(
 ```
 
 ```typescript TypeScript icon="square-js"
-const view = await db.createMaterializedView("recent_docs", {
-  source: "documents",
+const view = await db.createMaterializedView("recent_docs", "documents", {
   select: ["id", "title", "embedding"],
   where: "created_at > '2026-01-01'",
 });