Prevent code block creation when using markdown in slot

[silvester-pari]

When using markdown inside the slot, it happen easily that the indentation causes the creation of code blocks:

<eox-storytelling>
This creates a paragraph
</eox-storytelling>

    <eox-storytelling>
    This creates a code block
    </eox-storytelling>

This is because of the "indented code block" commonmark spec.

There is a way to disable this rule in markdown-it, which we probably should do for the slot-passed markdown by default.

[silvester-pari]

When disabling the code rule in markdown-it, there is an issue since everything renders as a paragraph instead. I consider it a bug and opened an issue: markdown-it/markdown-it#1014