title: TypeScript not finding the types in @types
body: <p>I am trying to import some types from <code>@types/webgl2</code> in my project.
  I have followed every bit of advice mentioned here:
  <a href="https://stackoverflow.com/questions/40441252/typescript-typings-give-me-index-d-ts-is-not-a-module">TypeScript typings give me &quot;index.d.ts is not a module&quot;</a></p>
  
  <p>Added this to the top: <code>import 'webgl2';</code></p>
  
  <ul>
  <li>I have made sure "<code>modeResolution</code>" is "<code>true</code>" in <code>tsconfig.json</code></li>
  <li>I added a line <code>"types":["webgl2"]</code> to my <code>tsconfig.json</code></li>
  <li>Added  <code>"@types/webgl2": "0.0.4"</code> to both <code>devDependencies</code> and <code>dependencies</code> in <code>package.json</code>.</li>
  <li>Did an npm install in my project folder:</li>
  </ul>
  
  <blockquote>
  <pre><code>npm WARN package.json webgl@0.0.1 No README data
  npm WARN package.json Dependency '@types/webgl2' exists in both dependencies and devDependencies, using '@types/webgl2@0.0.4' from  dependencies
  </code></pre>
  </blockquote>
  
  <p>I can easily see <code>webgl2</code> in <code>node_modules/@types</code> and I can also see the declaration for all errored symbols under:</p>
  
  <pre><code>declare var WebGl2RenderingContext {
  </code></pre>
  
  <p>and I still get these errors:</p>
  
  <pre><code>(multiple lines)
  Cannot find name 'WebGl2RenderingContext'. Did you mean 'WebGL2RenderingContext'?
  </code></pre>
  
  <p>Corresoonding to:</p>
  
  <pre><code>const format = WebGl2RenderingContext.RED;
  </code></pre>