title: VSCode extension API: autocomplete documentation/detail highlighting
body: <p>There is closed <a href="https://github.com/Microsoft/vscode/issues/34188" rel="nofollow noreferrer">issue on GitHub</a> that says the syntax highlighting is not enabled in autocomplete details.</p>
  <p>Here is the code for autocomplete that has no highlight</p>
  <pre><code>vscode.languages.registerCompletionItemProvider('xml', {
          provideCompletionItems(document: vscode.TextDocument, position: vscode.Position, token: vscode.CancellationToken): Thenable&lt;vscode.CompletionItem[]&gt;
          {
              return new Promise&lt;vscode.CompletionItem[]&gt;((resolve, reject) =&gt;
              {
                  let ci = new vscode.CompletionItem(&quot;tag&quot;, vscode.CompletionItemKind.Snippet);
                  ci.detail = &quot;&lt;Tag&gt;detail&lt;/Tag&gt;&quot;
                  ci.documentation = &quot;&lt;Tag&gt;documentation&lt;/Tag&gt;&quot;
                  ci.insertText = &quot;&lt;Tag&gt;&lt;/Tag&gt;&quot;;
                  resolve([ci]);
              });
          }
      }
  );
  </code></pre>
  <p>And here is snippet code that provides nice highlight</p>
  <pre><code>&quot;tag&quot;: {
      &quot;prefix&quot;: &quot;tag&quot;,
      &quot;body&quot;: &quot;&lt;Tag&gt;detail&lt;/Tag&gt;&quot;,
      &quot;description&quot;: &quot;&lt;Tag&gt;description&lt;/Tag&gt;&quot;
  }
  </code></pre>
  <p>So is there really no way to highlight the dynamic completion content like in snippet? looks strange...</p>