document inventory changed event objects

src/StardewModdingAPI/Inheritance/ChangeType.cs

@@ -1,9 +1,15 @@
 namespace StardewModdingAPI.Inheritance
 {
+    /// <summary>Indicates how an inventory item changed.</summary>
     public enum ChangeType
     {
+        /// <summary>The entire stack was removed.</summary>
         Removed,
+
+        /// <summary>The entire stack was added.</summary>
         Added,
+
+        /// <summary>The stack size changed.</summary>
         StackChange
     }
 }

src/StardewModdingAPI/Inheritance/ItemStackChange.cs

@@ -2,10 +2,19 @@
 
 namespace StardewModdingAPI.Inheritance
 {
+    /// <summary>Represents an inventory slot that changed.</summary>
     public class ItemStackChange
     {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The item in the slot.</summary>
         public Item Item { get; set; }
+
+        /// <summary>The amount by which the item's stack size changed.</summary>
         public int StackChange { get; set; }
+
+        /// <summary>How the inventory slot changed.</summary>
         public ChangeType ChangeType { get; set; }
     }
 }