max_stack should be usize

src/entity/item/tool.rs

@@ -218,7 +218,7 @@ impl ToolType {
         }
     }
 
-    pub fn max_stack(&self) -> u8 {
+    pub fn max_stack(&self) -> usize {
         match self {
             ToolType::Monomate => 10,
             ToolType::Dimate => 10,