updating sizing on contributing guide

CONTRIBUTING.md

@@ -1,12 +1,12 @@
 Contributing to OpenJDK for Windows on ARM64
 =====
 
-# Contributions to the source code
+## Contributions to the source code
 The source code can be found upstream on [openjdk.java.net](https://openjdk.java.net).
 Contributions are welcome through the [OpenJDK project](https://openjdk.java.net/contribute/).
 
-# Contributions to the documentation and other artifacts in this project
+## Contributions to the documentation and other artifacts in this project
 Pull Requests are welcome! Please note you may need to sign the [Microsoft Contributor License Agreement (CLA)](https://cla.opensource.microsoft.com/).
 
-# Code of Conduct
+## Code of Conduct
 Please see our [Code of Conduct](CODE_OF_CONDUCT.md).