Removed unused using directives.

Author: prochnowc

YamlDotNet.Analyzers.StaticGenerator/TypeFactoryGenerator.cs

@@ -20,9 +20,7 @@
 // SOFTWARE.
 
 using System;
-using System.Diagnostics;
 using System.Text;
-using System.Xml;
 using Microsoft.CodeAnalysis;
 
 namespace YamlDotNet.Analyzers.StaticGenerator