Show a hint for using locales with ES6 modules

Requested in https://github.com/transloadit/uppy/issues/1198#issuecomment-488238219

packages/@uppy/locales/README.md

@@ -20,8 +20,8 @@ $ npm install @uppy/core @uppy/locales --save
 ```
 
 ```js
-const Uppy = require('uppy/core')
-const Russian = require('uppy/locales/lib/ru_RU')
+const Uppy = require('@uppy/core')
+const Russian = require('@uppy/locales/lib/ru_RU')
 const uppy = Uppy({
   debug: true,
   meta: {

website/src/docs/uppy.md

@@ -219,6 +219,7 @@ Instead of overriding strings yourself, consider using [one of our language pack
 
 ```js
 const russianLocale = require('@uppy/locales/lib/ru_RU')
+// ^-- OR: import russianLocale from '@uppy/locales/lib/ru_RU'
 const uppy = Uppy({
   locale: russianLocale,
 })