diff -u b/core/modules/contact/src/MessageViewBuilder.php b/core/modules/contact/src/MessageViewBuilder.php
--- b/core/modules/contact/src/MessageViewBuilder.php
+++ b/core/modules/contact/src/MessageViewBuilder.php
@@ -56,7 +56,8 @@
 
     if ($view_mode == 'mail') {
       // Convert field labels into headings.
-      // @todo Improve \Drupal\Core\Mail\MailFormatHelper::htmlToText() to convert DIVs correctly.
+      // @todo Improve \Drupal\Core\Mail\MailFormatHelper::htmlToText() to
+      // convert DIVs correctly.
       foreach (Element::children($build) as $key) {
         if (isset($build[$key]['#label_display']) && $build[$key]['#label_display'] == 'above') {
           $build[$key] += array('#prefix' => '');
diff -u b/core/modules/system/src/Tests/Mail/HtmlToTextTest.php b/core/modules/system/src/Tests/Mail/HtmlToTextTest.php
--- b/core/modules/system/src/Tests/Mail/HtmlToTextTest.php
+++ b/core/modules/system/src/Tests/Mail/HtmlToTextTest.php
@@ -38,7 +38,8 @@
   }
 
   /**
-   * Helper function for testing \Drupal\Core\Mail\MailFormatHelper::htmlToText().
+   * Helper function for testing
+   * \Drupal\Core\Mail\MailFormatHelper::htmlToText().
    *
    * @param $html
    *   The source HTML string to be converted.
@@ -67,7 +68,8 @@
   }
 
   /**
-   * Test all supported tags of \Drupal\Core\Mail\MailFormatHelper::htmlToText().
+   * Test all supported tags of
+   * \Drupal\Core\Mail\MailFormatHelper::htmlToText().
    */
   public function testTags() {
     global $base_path, $base_url;
@@ -162,7 +164,8 @@
   }
 
   /**
-   * Test $allowed_tags argument of \Drupal\Core\Mail\MailFormatHelper::htmlToText().
+   * Test $allowed_tags argument of
+   * \Drupal\Core\Mail\MailFormatHelper::htmlToText().
    */
   public function testDrupalHtmlToTextArgs() {
     // The second parameter of \Drupal\Core\Mail\MailFormatHelper::htmlToText()