Right to left languages support

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Hi, Thanks for this great software ❤️

I tried to use macDown to author a Persian text which is a right-to-left language (Hebrew and Arabic are RTL too). But it fails to render that correctly. This is the raw markdown:

```

```php
for ($i=1; $i<=10; $i++) {
echo "hello";
}
*``` //remove the star
```

This will be rendered in Github as expected:

---

```php
for ($i=1; $i<=10; $i++) {
echo "hello";
}
```

---

But in macDown it fails to format the text enclosed in `

Start by reproducing the supplied Persian Markdown containing a dir='rtl' div in MacDown and compare its preview with the GitHub rendering shown in the issue. Trace the preview's handling of the HTML direction attribute; done means Hebrew, Arabic, and Persian content formats correctly while the existing code block and list remain intact.

Written by the indexing model from the issue text.