Modify rule S3168: Add more exceptions (#4547)

rules/S3168/csharp/rule.adoc

@@ -10,7 +10,10 @@ Doing so prevents control over the https://learn.microsoft.com/en-us/dotnet/csha
 
 === Exceptions
 
-* Methods with the https://learn.microsoft.com/en-us/dotnet/api/system.eventhandler[`EventHandler`] delegate signature.
+* Methods implementing an interface
+* Methods overriding a base class method
+* Virtual methods
+* Methods with the https://learn.microsoft.com/en-us/dotnet/api/system.eventhandler[`EventHandler`] delegate signature
 +
 Using `void` for `EventHandler` is compliant with the TAP model.
 +
@@ -21,9 +24,9 @@ public async void button1_Click(object sender, EventArgs e)
   await DoSomethingAsync();
 }
 ----
-* Methods name matching ``++On[A-Z]\w*++`` pattern.
+* Methods name matching ``++On[A-Z]\w*++`` pattern
 +
-Some frameworks may not use the same `EventHandler` method signature
+Some frameworks may not use the same `EventHandler` method signature.
 +
 [source,csharp]
 ----