C#: Address review comments (change description to use true/false instead of yes/no).

Author: michaelnebel

csharp/codeql-extractor.yml

@@ -33,7 +33,10 @@ options:
     title: Whether to use buildless (standalone) extraction.
     description: >
       A value indicating, which type of extraction the autobuilder should perform.
-      If 'yes', then the standalone extractor will be used, otherwise tracing extraction
+      If 'true', then the standalone extractor will be used, otherwise tracing extraction
       will be performed.
-      The default is 'no'.
+      The default is 'false'.
+      Note that buildless extraction will generally yield less accurate analysis results,
+      and should only be used in cases where it is not possible to build
+      the code (for example if it uses inaccessible dependencies).
     type: string

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

@@ -1,4 +1,4 @@
 ---
 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 `yes` 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).