prometheus/exporter.sls: fix Trailing whitespace

prometheus/exporter.sls

@@ -41,7 +41,7 @@ prometheus-node-exporter.service:
       - service: prometheus-node-exporter.service
     - require_in:
       - service: prometheus-node-exporter.service
-  module.run: 
+  module.run:
     - name: service.systemctl_reload
     - onchanges:
       - file: /etc/systemd/system/prometheus-node-exporter.service