title: TextMate grammar not having any matches on VS Code
body: <p>I am writing a TextMate grammar to extend the syntax highlighting capabilities on Markdown language using Visual Studio Code.
  The expected outcome is something like what is achieved with <a href="https://marketplace.visualstudio.com/items?itemName=fabiospampinato.vscode-highlight" rel="nofollow noreferrer">Fabio's vscode-highlight</a>, but I was looking for something more 'simple', without having the need to install or create an extension.</p>
  
  <p>Already did lots of research but can't get any matches when inspecting the scope. Any suggestions?
  As of now, my files are:</p>
  
  <strong><code>./package.json</code></strong>
  
  <pre class="lang-json prettyprint-override"><code>{
      "name": "name123",
      "description": "desc123",
      "publisher": "me",
      "version": "0.0.1",
      "engines": {
          "vscode": "^1.0.0"
      },
      "contributes": {
          "grammars": [{
              "language": "markdown",
              "scopeName": "text.html.markdown",
              "path": "./syntaxes/markdown.tmLanguage.json"
          }]
      }
  }
  </code></pre>
  
  <strong><code>./syntaxes/markdown.tmLanguage.json</code></strong>
  
  <pre class="lang-json prettyprint-override"><code>{
    "scopeName": "text.html.markdown",
    "patterns": [
      { "include": "#headings" }],
    "repository": {
      "headings": {
        "patterns": [
          { "include": "#symbol" },
          { "include": "#text" }]},
          "symbol": {
            "match": "*s2",
            "name": "symbol.letter.number.headings.md" },
          "text": {
            "match": "Description 12345",
            "name": "text.description.headings.md" }
    }
  }
  </code></pre>