Parse figcaption contents

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Feature Request

When using the figcaption option,

marked:
  figcaption: true

generating images as

<figure>
  <img ... >
  <figcaption>...</figcaption>
</figure>

the figcaptions are usually intended to be rendered in some fancy way, including links or styles, etc.

I think it would be useful to parse its contents, changing from:

      return `<figure>${out}<figcaption aria-hidden="true">${text}</figcaption></figure>`;

to

      return `<figure>${out}<figcaption aria-hidden="true">${marked.parse(text)}</figcaption></figure>`;

If the figcaption has no special markdown, there is no difference. If we include some kind of markdown content, it will be parsed.

Additional context

No response