doc: remove "What's New" documentation pages (#492)

Author: sindharta

com.unity.toonshader/Documentation~/TableOfContents.md

@@ -1,14 +1,6 @@
 * [Unity Toon Shader](index.md)
 * [Requirements](System-Requirements.md)
 * [Installation](installation.md)
-* [What's new](whats-new.md)
-  * [0.10.x-preview](whats-new-0.10.x.md)
-  * [0.9.x-preview](whats-new-0.9.x.md)
-  * [0.8.x-preview](whats-new-0.8.x.md)
-  * [0.7.x-preview](whats-new-0.7.x.md)
-  * [0.6.x-preview](whats-new-0.6.x.md)
-  * [0.5.0-preview](whats-new-0.5.x.md)
-  * [0.3.0-preview](whats-new-0.3.x.md)
 * [Getting started](GettingStarted.md)
 * [Material Converter](MaterialConverter.md)
 * [Inspector Window Settings](Parameter-Settings.md)