title: Invalid component name: "pages/product/_slug.vue". Component names should conform to valid custom element name in html5 specification
body: <p>I am using Nuxt.js and have some dynamic routes. My folder structure is this:</p>
  
  <pre><code>- pages
   - product
    - _slug.vue
  </code></pre>
  
  <p>I link to the route like this: </p>
  
  <pre><code>&lt;nuxt-link :to="{ name: 'product-slug', params: { slug: product.slug } }"&gt;
  </code></pre>
  
  <p>It works fine, it shows the correct URL and also directs the page fine, however, I am getting an annoying red error in my console:</p>
  
  <pre><code>[Vue warn]: Invalid component name: "pages/product/_slug.vue". Component names should conform to valid custom element name in html5 specification.
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/EYKRl.png" rel="noreferrer"><img src="https://i.stack.imgur.com/EYKRl.png" alt="enter image description here"></a></p>
  
  <p>I have found this issue, but to little avail: <a href="https://github.com/nuxt/nuxt.js/issues/165" rel="noreferrer">https://github.com/nuxt/nuxt.js/issues/165</a></p>