Add Effect.elm to elm-application.json for end-to-end app.

examples/end-to-end/elm-application.json

@@ -3,6 +3,7 @@
     "summary": "Offline documentation previewer",
     "version": "5.0.0",
     "exposed-modules": [
-        "Page"
+        "Page",
+        "Effect"
     ]
 }