VOLDEV-34: Parse [[wikilinks]] in Forum/Wall log actions

Follow-up to #2224

@Grunny @michalroszka @hakubo
You can go with short tags here as well:
```php
<div class="reason"><?= Linker::formatComment( $statusInfo['reason'] ); ?></div>
```

and then to be consistent use it in whole `Wall_statusInfoBox.php` file (it isn't too big, I guess).