Getting rid of awkward reset overload

ReactiveDerivedCollection needs to override the implementation of Reset
while still being able to use SuppressChangeNotification. My previous
hack to allow this needs to be killed with fire so I'm adding
publishResetNotification to ReactiveCollection. It's not ideal but at
least it's better than the previous version.

ReactiveUI/ReactiveCollection.cs

@@ -282,27 +282,28 @@ public virtual void RemoveAll(IEnumerable<T> items)
         public virtual void Sort(int index, int count, IComparer<T> comparer)
         {
             _inner.Sort(index, count, comparer);
-            Reset(true);
+            Reset();
         }
 
         public virtual void Sort(Comparison<T> comparison)
         {
             _inner.Sort(comparison);
-            Reset(true);
+            Reset();
         }
 
         public virtual void Sort(IComparer<T> comparer = null)
         {
             _inner.Sort(comparer ?? Comparer<T>.Default);
-            Reset(true);
+            Reset();
         }
 
         public virtual void Reset()
         {
-            Reset(true);
+            publishResetNotification();
         }
 
-        protected virtual void Reset(bool resetting)
+
+        protected virtual void publishResetNotification()
         {
             var ea = new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset);
             _changing.OnNext(ea);
@@ -349,7 +350,7 @@ public IDisposable SuppressChangeNotifications()
 
             return Disposable.Create(() => {
                 if (Interlocked.Decrement(ref _suppressionRefCount) == 0) {
-                    Reset(true);
+                    publishResetNotification();
                 }
             });
         }