docs(routes): update comments for mock Switch test component

src/__mocks__/react-router-transition.js

@@ -1,7 +1,7 @@
 import React from 'react';
 
-// mock the AnimatedSwitch with the normal Switch for testing
-// because it raises an error, but works fine in the app
+// mock the AnimatedSwitch with the normal Switch
+// it raises an error in tests, but works fine in the app
 const MockSwitch = props => {
   // need to call mapStyles to get proper test coverage
   props.mapStyles({});