Update to Drupal 8.1.2. For more information, see https://www.drupal.org/project/drupal/releases/8.1.2

core/modules/forum/forum.module

@@ -29,7 +29,7 @@ function forum_help($route_name, RouteMatchInterface $route_match) {
       $output .= '<li>' . t('<em>Forums</em> (for example, <em>Recipes for cooking vegetables</em>)') . '</li>';
       $output .= '<li>' . t('<em>Forum topics</em> submitted by users (for example, <em>How to cook potatoes</em>), which start discussions.') . '</li>';
       $output .= '<li>' . t('Threaded <em>comments</em> submitted by users (for example, <em>You wash the potatoes first and then...</em>).') . '</li>';
-      $output .= '<li>' . t('Optional <em>containers</em>, used to group similar forums. Forums can be placed inside containers, and vice versa.').'</li>';
+      $output .= '<li>' . t('Optional <em>containers</em>, used to group similar forums. Forums can be placed inside containers, and vice versa.') . '</li>';
       $output .= '</ul>';
       $output .= '</p>';
       $output .= '<p>' . t('For more information, see the <a href=":forum">online documentation for the Forum module</a>.', array(':forum' => 'https://www.drupal.org/documentation/modules/forum')) . '</p>';
@@ -282,7 +282,7 @@ function forum_comment_delete(CommentInterface $comment) {
 }
 
 /**
- * Implements hook_form_BASE_FORM_ID_alter().
+ * Implements hook_form_BASE_FORM_ID_alter() for \Drupal\taxonomy\VocabularyForm.
  */
 function forum_form_taxonomy_vocabulary_form_alter(&$form, FormStateInterface $form_state, $form_id) {
   $vid = \Drupal::config('forum.settings')->get('vocabulary');
@@ -304,7 +304,7 @@ function forum_form_taxonomy_vocabulary_form_alter(&$form, FormStateInterface $f
 }
 
 /**
- * Implements hook_form_FORM_ID_alter() for taxonomy_term_form().
+ * Implements hook_form_FORM_ID_alter() for \Drupal\taxonomy\TermForm.
  */
 function forum_form_taxonomy_term_form_alter(&$form, FormStateInterface $form_state, $form_id) {
   $vid = \Drupal::config('forum.settings')->get('vocabulary');
@@ -315,7 +315,7 @@ function forum_form_taxonomy_term_form_alter(&$form, FormStateInterface $form_st
 }
 
 /**
- * Implements hook_form_BASE_FORM_ID_alter() for node_form().
+ * Implements hook_form_BASE_FORM_ID_alter() for \Drupal\node\NodeForm.
  */
 function forum_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
   $node = $form_state->getFormObject()->getEntity();

core/modules/forum/src/Breadcrumb/ForumBreadcrumbBuilderBase.php

@@ -17,7 +17,7 @@ use Drupal\forum\ForumManagerInterface;
  * This just holds the dependency-injected config, entity manager, and forum
  * manager objects.
  */
-abstract class ForumBreadcrumbBuilderBase  implements BreadcrumbBuilderInterface {
+abstract class ForumBreadcrumbBuilderBase implements BreadcrumbBuilderInterface {
   use StringTranslationTrait;
 
   /**

core/modules/forum/src/Form/Overview.php

@@ -10,7 +10,7 @@ use Drupal\taxonomy\Form\OverviewTerms;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 
-/*
+/**
  * Provides forum overview form for the forum vocabulary.
  */
 class Overview extends OverviewTerms {

core/modules/forum/src/Plugin/Block/NewTopicsBlock.php

@@ -24,4 +24,5 @@ class NewTopicsBlock extends ForumBlockBase {
       ->orderBy('f.created', 'DESC')
       ->range(0, $this->configuration['block_count']);
   }
+
 }

core/modules/forum/src/Plugin/Validation/Constraint/ForumLeafConstraint.php

@@ -16,4 +16,5 @@ class ForumLeafConstraint extends Constraint {
 
   public $selectForum = 'Select a forum.';
   public $noLeafMessage = 'The item %forum is a forum container, not a forum. Select one of the forums below instead.';
+
 }

core/modules/forum/src/Tests/ForumBlockTest.php

@@ -176,4 +176,5 @@ class ForumBlockTest extends WebTestBase {
 
     return $topics;
   }
+
 }

core/modules/forum/src/Tests/ForumIndexTest.php

@@ -79,4 +79,5 @@ class ForumIndexTest extends WebTestBase {
     $this->drupalGet('forum/' . $tid);
     $this->assertNoText($title, 'Unpublished forum topic no longer appears on index.');
   }
+
 }

core/modules/forum/src/Tests/ForumTest.php

@@ -678,4 +678,5 @@ class ForumTest extends WebTestBase {
       $this->nids[] = $node->id();
     }
   }
+
 }

core/modules/forum/src/Tests/ForumUninstallTest.php

@@ -138,7 +138,7 @@ class ForumUninstallTest extends WebTestBase {
     // Delete all terms in the Forums vocabulary. Uninstalling the forum module
     // will fail unless this is done.
     $terms = entity_load_multiple_by_properties('taxonomy_term', array('vid' => 'forums'));
-    foreach($terms as $term) {
+    foreach ($terms as $term) {
       $term->delete();
     }