title: How to hint vscode about the file type within the file?
body: <p>Visual Studio Code documentation for <a href="https://code.visualstudio.com/docs/languages/identifiers" rel="nofollow noreferrer">Language Identifiers</a> explains how to map file extensions to language definitions.</p>
  <p><strong>Is there a way to provide this hint within the file itself?</strong></p>
  <ul>
  <li><p>A possibility could be to have this information in a comment. I realize that in order to have this, one must first know what a comment is (and it varies by language, which is not known yet, thus some catch-22 situation).</p>
  </li>
  <li><p>Another one could be the special meaning of the first line of the file.</p>
  </li>
  </ul>
  <p>None such possibilities were provided in the documentation, I am asking the question in case there is something else available anyway (through an extension for instance)</p>