docs: add syntax highlighting for typescript (#1345)

According to Docsify docs (https://docsify.js.org/#/language-highlight?id=language-highlighting)
only few languages are supported by default by Prism (the underlying lib), and TypeScript is not.
This commit aims to add such support on TypeScript snippets like the one at `web` page.

index.html

@@ -47,5 +47,7 @@
 <script src="//unpkg.com/docsify/lib/docsify.min.js"></script>
 <script src="//unpkg.com/docsify/lib/plugins/search.min.js"></script>
 <script src="//unpkg.com/docsify/lib/plugins/ga.min.js"></script>
+<!-- To enable syntax highlighting on TypeScript codes: -->
+<script src="//cdn.jsdelivr.net/npm/prismjs@1/components/prism-typescript.min.js"></script>
 
 </html>