Removed comment at the closing brace of Extension Query Classes to conform psr-1/psr-2

Currently the Extension Query class will be generated like this:
```php
<?php

namespace MyApp;

use MyApp\Base\UserQuery as BaseUserQuery;

class UserQuery extends BaseUserQuery
{
} // ClientQuery
```

php codesniffer with the psr2 ruleset complains about the the last line. There should be no comment because the closing brace must be on a line by itself.

It's also inconsistent with the ExtensionObjectBuilder: The Extension Objects don't have a comment at the closing brace of the class definition.

With this patch the generate code above will look like this:
```php
<?php

namespace MyApp;

use MyApp\Base\UserQuery as BaseUserQuery;

class UserQuery extends BaseUserQuery
{
}
```