small fixes from PR review to pull request #2757

ui/src/kapacitor/components/AlertTabs.js

@@ -89,7 +89,7 @@ class AlertTabs extends Component {
         const errorMsg = _.join(_.drop(_.split(error, ': '), 2), ': ')
         this.props.addFlashMessage({
           type: 'error',
-          text: `There was an error saving the alert configuration for ${section}. ${errorMsg}`,
+          text: `There was an error saving the alert configuration for ${section}: ${errorMsg}`,
         })
         return false
       }

ui/src/kapacitor/components/config/SMTPConfig.js

@@ -76,6 +76,7 @@ class SMTPConfig extends Component {
           <input
             className="form-control"
             id="smtp-to"
+            placeholder="email@domain.com"
             type="text"
             ref={r => (this.to = r)}
             defaultValue={to || ''}