docs: add maxCount description

Author: aojunhao123

README.md

@@ -70,6 +70,7 @@ online example: https://tree-select-react-component.vercel.app/
 | allowClear               | whether allowClear                                                                                                                                                                  | bool                                                                                                                                                                                                                           | false                             |
 | maxTagTextLength         | max tag text length to show                                                                                                                                                         | number                                                                                                                                                                                                                         | -                                 |
 | maxTagCount              | max tag count to show                                                                                                                                                               | number                                                                                                                                                                                                                         | -                                 |
+| maxCount                 | Limit the maximum number of items that can be selected in multiple mode                                                                                                             | number                                                                                                                                                                                                                         | -                                 |
 | maxTagPlaceholder        | placeholder for omitted values                                                                                                                                                      | ReactNode/function(omittedValues)                                                                                                                                                                                              | -                                 |
 | multiple                 | whether multiple select (true when enable treeCheckable)                                                                                                                            | bool                                                                                                                                                                                                                           | false                             |
 | disabled                 | whether disabled select                                                                                                                                                             | bool                                                                                                                                                                                                                           | false                             |

src/OptionList.tsx

@@ -128,10 +128,8 @@ const OptionList: React.ForwardRefRenderFunction<ReviseRefOptionListProps> = (_,
       return;
     }
 
-    const isSelected = !checkedKeys.includes(node.key);
-
     onSelect(node.key, {
-      selected: isSelected,
+      selected: !checkedKeys.includes(node.key),
     });
 
     if (!multiple) {