Fenced code encapsuled

[ElGigi]

Encapsuled fenced code doesn't works.

````markdown
```mermaid
graph LR
    Start --> Stop
```
````

To fix this issue:

    protected function blockFencedCode($Line)
    {
        if (preg_match('/^([' . $Line['text'][0] . ']{3,})[ ]*([^`]+)?[ ]*$/', $Line['text'], $matches)) {
            $Element = [
                'name' => 'code',
                'text' => '',
            ];

            if (isset($matches[2])) {
                $class = 'language-' . $matches[2];

                $Element['attributes'] = [
                    'class' => $class,
                ];
            }

            $Block = [
                'char'    => $Line['text'][0],
                'element' => [
                    'name'    => 'pre',
                    'handler' => 'element',
                    'text'    => $Element,
                    'length'  => mb_strlen($matches[1]),
                ],
            ];

            return $Block;
        }
    }

    protected function blockFencedCodeContinue($Line, $Block)
    {
        if (isset($Block['complete'])) {
            return;
        }

        if (isset($Block['interrupted'])) {
            $Block['element']['text']['text'] .= "\n";

            unset($Block['interrupted']);
        }

        if (preg_match('/^' . $Block['char'] . '{' . $Block['element']['length'] . '}[ ]*$/', $Line['text'])) {
            $Block['element']['text']['text'] = substr($Block['element']['text']['text'], 1);

            $Block['complete'] = true;

            return $Block;
        }

        $Block['element']['text']['text'] .= "\n" . $Line['body'];

        return $Block;
    }

[aidantwoods]

Thanks @ElGigi! :)