docs: add brief note about how to check types manually (#1822)

docs/content/2.concepts/3.typescript.md

@@ -2,6 +2,14 @@
 
 Nuxt 3 is fully typed and provides helpful shortcuts to ensure you have access to accurate type information when you are coding.
 
+## Type-checking
+
+By default Nuxt doesn't check types when you run `nuxi dev` or `nuxi build`, for performance reasons. However, you can manually check your types using [`vue-tsc`](https://github.com/johnsoncodehk/volar/tree/master/packages/vue-tsc).
+
+```bash
+npx vue-tsc --noEmit
+```
+
 ## Auto-generated types
 
 When you run `nuxi dev` or `nuxi build`, the following files are generated for IDE type support (and type-checking):