Add ShowRowSeparators in Table Widget docs (#1807)

Author: bartoginski

docs/input/widgets/table.md

@@ -137,4 +137,11 @@ table.Columns[0].NoWrap();
 ```csharp
 // Set the column width
 table.Columns[0].Width(15);
+```
+
+### Show row separators
+
+```csharp
+// Shows separator between each row
+table.ShowRowSeparators();
 ```