fix: properly return empty string for custom blocks

Author: harlan-zw

src/loaders/pitcher.ts

@@ -18,7 +18,7 @@ export const pitch = function(this: webpack.loader.LoaderContext, remainingReque
 
   // ignore custom block
   if (remainingRequest.includes('&type=custom'))
-    return
+    return ''
 
   // make sure we're dealing with style-loader
   if (!remainingRequest.includes('&type=style'))

test/fixtures/vue/templates/App.vue

@@ -46,6 +46,12 @@
   </div>
 </template>
 
+<config>
+{
+ "name": "editor"
+}
+</config>
+
 <script>
 export default {
   name: 'App',