C#: Bugfix in the implicittostring. Need to handle the ReadOnlySpan params overload for string.Format.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/commons/Strings.qll

@@ -3,6 +3,7 @@
  */
 
 import csharp
+private import semmle.code.csharp.commons.Collections
 private import semmle.code.csharp.frameworks.Format
 private import semmle.code.csharp.frameworks.System
 private import semmle.code.csharp.frameworks.system.Text
@@ -33,7 +34,7 @@ class ImplicitToStringExpr extends Expr {
       or
       p instanceof StringFormatItemParameter and
       not p.getType() =
-        any(ArrayType at |
+        any(ParamsCollectionType at |
           at.getElementType() instanceof ObjectType and
           this.getType().isImplicitlyConvertibleTo(at)
         )