Modernize code: very last fixes (#6290)

Last modernization fixes

src/inventory.h

@@ -32,11 +32,12 @@ struct ToolCapabilities;
 
 struct ItemStack
 {
-	ItemStack() {}
+	ItemStack() = default;
+
 	ItemStack(const std::string &name_, u16 count_,
 			u16 wear, IItemDefManager *itemdef);
 
-	~ItemStack() {}
+	~ItemStack() = default;
 
 	// Serialization
 	void serialize(std::ostream &os) const;
@@ -132,10 +133,8 @@ struct ItemStack
 				wear += amount;
 			return true;
 		}
-		else
-		{
-			return false;
-		}
+
+		return false;
 	}
 
 	// If possible, adds newitem to this item.