corrected misspelling in percent_metrics (#17856)

CONTRIBUTING.md

@@ -1358,7 +1358,7 @@ Note not all fields are correctly categorized. The fields vary based on visualiz
 | `columns`                                                                                              | _array(string)_                                   | The **Breakdowns** widget                         |
 | `groupby`                                                                                              | _array(string)_                                   | The **Group by** or **Series** widget             |
 | `limit`                                                                                                | _number_                                          | The **Series Limit** widget                       |
-| `metric`<br>`metric_2`<br>`metrics`<br>`percent_mertics`<br>`secondary_metric`<br>`size`<br>`x`<br>`y` | _string_,_object_,_array(string)_,_array(object)_ | The metric(s) depending on the visualization type |
+| `metric`<br>`metric_2`<br>`metrics`<br>`percent_metrics`<br>`secondary_metric`<br>`size`<br>`x`<br>`y` | _string_,_object_,_array(string)_,_array(object)_ | The metric(s) depending on the visualization type |
 | `order_asc`                                                                                            | _boolean_                                         | The **Sort Descending** widget                    |
 | `row_limit`                                                                                            | _number_                                          | The **Row limit** widget                          |
 | `timeseries_limit_metric`                                                                              | _object_                                          | The **Sort By** widget                            |