title: Why does changing app.js to app.tsx break my Next.js project?
body: <p>I'm trying to set up the Next.js framework with TypeScript, and I'm able to change my <code>pages/index.js</code> page to an <code>pages/index.tsx</code> page without issue, but when I attempt to change <code>pages/_app.js</code> to <code>pages/_app.tsx</code>, the project breaks with the error:</p>
  <p>Error: ENOENT: no such file or directory, open <code>/../../pages/_app.js</code></p>
  <p>Why is this happening? I've installed TypeScript, @types/react, and @types/node</p>