Docs: Update prometheus.md (#28483)

docs/sources/datasources/prometheus.md

@@ -90,11 +90,11 @@ provides the following functions you can use in the `Query` input field.
 
 
 | Name                             | Description                                                             |
 | Name                             | Description                                                             |
 | -------------------------------- | ----------------------------------------------------------------------- |
 | -------------------------------- | ----------------------------------------------------------------------- |
-| `label`\``names()`               | Returns a list of label names.                                          |
-| `label`\``values(label)`         | Returns a list of label values for the `label` in every metric.         |
-| `label`\``values(metric, label)` | Returns a list of label values for the `label` in the specified metric. |
+| `label_\__names()`               | Returns a list of label names.                                          |
+| `label_\__values(label)`         | Returns a list of label values for the `label` in every metric.         |
+| `label_\__values(metric, label)` | Returns a list of label values for the `label` in the specified metric. |
 | `metrics(metric)`                | Returns a list of metrics matching the specified `metric` regex.        |
 | `metrics(metric)`                | Returns a list of metrics matching the specified `metric` regex.        |
-| `query`\``result(query)`         | Returns a list of Prometheus query result for the `query`.              |
+| `query_\__result(query)`         | Returns a list of Prometheus query result for the `query`.              |
 
 
 For details of what _metric names_, _label names_ and _label values_ are please refer to the [Prometheus documentation](http://prometheus.io/docs/concepts/data_model/#metric-names-and-labels).
 For details of what _metric names_, _label names_ and _label values_ are please refer to the [Prometheus documentation](http://prometheus.io/docs/concepts/data_model/#metric-names-and-labels).