remark-captions: allow setting custom class per type

[changethe]

hey, thanks for this awesome plugin.

it would be really helpful for styling etc if it was possible to set a custom class to the figure per type.
for example <figure class="table-figure">

[StaloneLab]

Hello @changethe 👋

Thanks for the suggestion, the change you suggest should be fairly easy to implement.
Unfortunately, I will likely not have much time to work on it soon, but if you are interested in implementing it, I could guide you through the process.

[changethe]

inspired by your plugin, I have already created my own version with what I wanted: https://github.com/changethe/remark-figcaptions

thanks a lot!