docs(site): i18n handler, prettier code blocks and highlighting (#951)

* fix: sirv, commonjs plugin, add rollup sig

* replace deprecated rollup plugins

* remove dollarsign

* fix i18n setting, code snippet styling, lng switch

* fix segment, rm unused styles

site/docs/integrate/01-singlepageapp.en.md

@@ -15,6 +15,8 @@ This flow has great support with most modern languages and frameworks and is the
 
 #### Typescript Authentication Example
 
+---
+
 If you use a framework like Angular, Vue, React, ... you can use this code snippet here to integrate **ZITADEL** into you application
 
 Library used for this example [https://github.com/IdentityModel/oidc-client-js](https://github.com/IdentityModel/oidc-client-js)
@@ -60,3 +62,5 @@ export default class AuthService {
     }
 }
 ```
+
+---