Remove unnecessary remark from ObservableCollection.CollectionChanged (#67250)

Co-authored-by: carlossanlop <[email protected]>

Author: carlossanlop

src/libraries/System.ObjectModel/src/System/Collections/ObjectModel/ObservableCollection.cs

@@ -80,9 +80,6 @@ event PropertyChangedEventHandler? INotifyPropertyChanged.PropertyChanged
         /// <summary>
         /// Occurs when the collection changes, either by adding or removing an item.
         /// </summary>
-        /// <remarks>
-        /// see <seealso cref="INotifyCollectionChanged"/>
-        /// </remarks>
         [field: NonSerialized]
         public virtual event NotifyCollectionChangedEventHandler? CollectionChanged;