Proposal to add target and ref parameters to the figure shortcode

Hello,

The HTML <a> tag can use a target attribute to tell the browser if the link needs to open in the same tab or a new one. The rel attribute goes hand in hand with target (in case someone wants to specify that too).

At the moment, the figure shortcode assigns only the href in the embedded <a> tag.

I am proposing supporting optional target and rel parameters for that shortcode.

If there’s no problem with this proposal, I can start working on the PR.

Oh well, I didn’t expect such an “overwhelming” response.

In any case, I have submitted this PR, with new tests, and all the old/new tests passing: