Update src/Neo.VM/Types/Map.cs

Co-authored-by: Shargon <shargon@gmail.com>

src/Neo.VM/Types/Map.cs

@@ -56,7 +56,7 @@ public StackItem this[PrimitiveType key]
                         ReferenceCounter.AddReference(key, this);
                     if (value is CompoundType { ReferenceCounter: null })
                     {
-                        throw new InvalidOperationException("Can not set a CompoundType without a ReferenceCounter.");
+                        throw new InvalidOperationException("Can not set a Map without a ReferenceCounter.");
                     }
                     ReferenceCounter.AddReference(value, this);
                 }