C#: Include example fragment in the release note on, how to invoke the extractor with the optional parameter.

Author: michaelnebel

csharp/ql/src/change-notes/2022-02-24-buildless-extractor-option.md

@@ -1,4 +1,5 @@
 ---
 category: minorAnalysis
 ---
-* The C# extractor now accepts an extractor option `buildless`, which is used to decide what type of extraction that should be performed. If `true` then buildless (standalone) extraction will be performed. Otherwise tracing extraction will be performed (default).
+* The C# extractor now accepts an extractor option `buildless`, which is used to decide what type of extraction that should be performed. If `true` then buildless (standalone) extraction will be performed. Otherwise tracing extraction will be performed (default).
+The option is added via `codeql database create --language=csharp -Obuildless=true ...`.