mod(mouse): fix input.Mouse.in method

Pass through mouse events where they actually match the corresponding
`Container`. Adopt mouse event accordingly in `Scrollable` `Element`
trait when passing through the mouse event to the scrollable
`Container`.

src/input.zig

@@ -36,8 +36,8 @@ pub const Mouse = packed struct {
     }
 
     pub fn in(this: @This(), size: Size) bool {
-        return this.col >= size.anchor.col and this.col <= size.cols -| size.anchor.col and
-            this.row >= size.anchor.row and this.row <= size.rows -| size.anchor.row;
+        return this.col >= size.anchor.col and this.col <= size.cols + size.anchor.col and
+            this.row >= size.anchor.row and this.row <= size.rows + size.anchor.row;
     }
 };