Added ChilliCream/hotchocolate to c# implementations list (graphql#538)

Author: michaelstaib

site/code/index.html.js

@@ -42,6 +42,7 @@ In addition to the GraphQL [reference implementations in JavaScript](#javascript
 
   - [graphql-dotnet](https://github.com/graphql-dotnet/graphql-dotnet): GraphQL for .NET
   - [graphql-net](https://github.com/ckimes89/graphql-net): Convert GraphQL to IQueryable
+  - [Hot Chocolate](https://github.com/ChilliCream/hotchocolate): GraphQL Service for .net core and .net classic
 
 ### Clojure