Section "Extending Blade" is wrong

[carcinocron]

This is wrong:

The following example creates a `@datetime($var)` directive which simply calls `->format()` on `$var`:

    Blade::extend(function($view, $compiler)
    {
        $pattern = $compiler->createMatcher('datetime');

        return preg_replace($pattern, '$1<?php echo $2->format('m/d/Y H:i'); ?>', $view);
    });

This has 2 errors in it:

1. 'm/d/Y H:i' isn't properly escaped.
2. @datetime($var) becomes ($var)->format() and crashes instead of $var->format()

Previous discussion: laravel/framework#4770 and #835