title: Vue mixins unresolved function or method in template
body: <p>I created a global function file:</p>
  <pre><code>module.exports = {
    methods: {
      t(key, replace = {}) {
        return 'test';
      }
    }
  }
  </code></pre>
  <p>And I imported that to app with:</p>
  <pre><code>.mixin(require('./base'))
  </code></pre>
  <p>And this method works, but in my IDE (PhpStorm) is displaying error <code>Unresolved function or method t</code> in Vue files. How to display hints for functions like that?</p>