Explore: Apply tab completion suggestion on Enter (#12904)

- if the suggestions menu is open, apply the selected item on Enter
- if not open, run the queries

public/app/containers/Explore/QueryField.tsx

@@ -331,7 +331,7 @@ class QueryField extends React.Component<TypeaheadFieldProps, TypeaheadFieldStat
         }
         break;
       }
-
+      case 'Enter':
       case 'Tab': {
         if (this.menuEl) {
           // Dont blur input