Remove unnecessary code

Add some comments

Author: Cyperghost

wcfsetup/install/files/lib/data/attachment/AttachmentList.class.php

@@ -53,7 +53,7 @@ private function loadFiles(): void
         FileRuntimeCache::getInstance()->cacheObjectIDs($fileIDs);
 
         foreach ($this->objects as $attachment) {
-            $file = FileRuntimeCache::getInstance()->getObject($attachment->fileID) ?? null;
+            $file = FileRuntimeCache::getInstance()->getObject($attachment->fileID);
             if ($file !== null) {
                 $attachment->setFile($file);
             }

wcfsetup/install/files/lib/data/user/UserProfile.class.php

@@ -391,6 +391,11 @@ public function getAvatar()
         return $this->avatar;
     }
 
+    /**
+     * Sets the user's avatar.
+     *
+     * @since 6.2
+     */
     public function setFileAvatar(File $file): void
     {
         $this->avatar = new AvatarDecorator($file);

wcfsetup/install/files/lib/system/file/processor/UserAvatarFileProcessor.class.php

@@ -65,7 +65,7 @@ public function adopt(File $file, array $context): void
             return;
         }
 
-        // Save the `fileID` in the session variable so that the current user can delete it the old avatar
+        // Save the `fileID` in the session variable so that the current user can delete the old avatar
         if ($user->avatarFileID !== null) {
             WCF::getSession()->register(\sprintf(self::SESSION_VARIABLE, $user->avatarFileID), TIME_NOW);
             WCF::getSession()->update();
@@ -146,11 +146,6 @@ public function canDownload(File $file): bool
     public function getThumbnailFormats(): array
     {
         return [
-            // TODO did we need thumbnails for sizes less then 128x128?
-            // 96x96
-            // 64x64
-            // 48x48
-            // 32x32
             new ThumbnailFormat(
                 '128',
                 UserAvatarFileProcessor::AVATAR_SIZE,