Update README.md

fix the description error

src/extensions/filter-control/README.md

@@ -59,7 +59,7 @@ Dependence if you use the datepicker option: [bootstrap-datepicker](https://gith
 ### filterData
 
 * type: String
-* description: Set custom select filter values, use `var:variable` to load from a variable or `url:http://www.example.com/data.json` to load from a remote json file or `jso:{key:data}` to load from a json string.
+* description: Set custom select filter values, use `var:variable` to load from a variable or `url:http://www.example.com/data.json` to load from a remote json file or `json:{key:data}` to load from a json string.
 * default: `undefined`
 
 ### filterDatepickerOptions