Update .editorconfig for C# code style preferences

- Added and modified code style settings, including:
  - Extended property patterns
  - Readonly struct members
  - Primary constructors
- Set diagnostic rule SA1625 severity to silent
- Added a description header for code analysis rules

.editorconfig

@@ -235,7 +235,7 @@ dotnet_diagnostic.SA1625.severity = silent
 csharp_style_prefer_primary_constructors = true:suggestion
 csharp_prefer_static_anonymous_function = true:suggestion
 
-# Rules for Skanetrafikens C# projects
+
 # Description: Code analysis rules for this project.
 
 # Code files