remove superfluous comment (#55634)

Fix #55389

Author: eiriktsarpalis

src/libraries/System.Collections/src/System/Collections/Generic/LinkedList.cs

@@ -177,7 +177,7 @@ public void Clear()
             while (current != null)
             {
                 LinkedListNode<T> temp = current;
-                current = current.Next;   // use Next the instead of "next", otherwise it will loop forever
+                current = current.Next;
                 temp.Invalidate();
             }