Improve formatting of 0.0.9 release notes

Author: tamasvajk

csharp/ql/lib/CHANGELOG.md

@@ -2,9 +2,9 @@
 
 ### Major Analysis Improvements
 
-Added support for C# 10 lambda improvements
-* Explicit return types on lambda expressions.
-* Lambda expression can be tagged with method and return value attributes.
+* Added support for C# 10 lambda improvements
+  * Explicit return types on lambda expressions.
+  * Lambda expression can be tagged with method and return value attributes.
 * Added support for C# 10 [Extended property patterns](https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-10#extended-property-patterns).
 * Return value attributes are extracted.
 * The QL `Attribute` class now has subclasses for each kind of attribute.