Add screenshot to README

Author: Youssef1313

README.md

@@ -12,3 +12,7 @@ That's true. But not all developers work on Visual Studio. Some developers might
 
 - For fun, if you just want to see what's the syntax tree Roslyn is generating.
 - For writing Roslyn's analyzers and codefixes requies knowledge of how the syntax tree for the case you're inspecting looks like.
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+## Screenshot
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+![image](https://user-images.githubusercontent.com/31348972/85202525-31363300-b307-11ea-8b96-2d44fc742bf4.png)