Update README.md

Author: HC200ok

README.md

@@ -26,7 +26,6 @@ https://hc200ok.github.io/vue3-easy-data-table-doc/
 13. [Fixed columns](https://hc200ok.github.io/vue3-easy-data-table-doc/features/fixed-column.html) (new feature since version `1.2.10`)
 14. [Header slot](https://hc200ok.github.io/vue3-easy-data-table-doc/features/header-slot.html) (new feature since version `1.2.25`)
 15. [Expand slot](https://hc200ok.github.io/vue3-easy-data-table-doc/features/expand-slot.html) (new feature since version `1.3.2`)
-15. [Expand slot](https://hc200ok.github.io/vue3-easy-data-table-doc/features/expand-slot.html) (new feature since version `1.3.2`)
 16. [Style customization](https://hc200ok.github.io/vue3-easy-data-table-doc/features/style-customization.html) (new feature since version `1.3.11`)
 17. [Border cell](https://hc200ok.github.io/vue3-easy-data-table-doc/features/border-cell.html) (new feature since version `1.3.11`)
 18. [Class name customization](http://localhost:8080/vue3-easy-data-table-doc/features/class-name-customization.html) (new feature since version `1.3.11`)