Docs redesign (#728)

* Adding a dark mode
* Adding reference for types to summary pages
* Adding API Reference
* Adding modifiers to methods/fields/etc
* Minimizing files input
* Caching a lot of the output pages
* Cache only for each execution
* Adding API references to existing docs

docs/src/Models/Emoji.cs

@@ -1,6 +1,4 @@
-using System;
 using System.Collections.Generic;
-using System.Text;
 using Newtonsoft.Json;
 
 namespace Docs.Models