Fix figure linkattr parameter

[ahelwer]

Have to use $ to operate from the root scope inside a with Closes #258

[ahelwer]

Yeah I actually use a fork of this theme where the only change is that this figure shortcode is deleted. Some problems I've found with it:

• Markdown in caption isn't rendered #322
• Very weird method of rendering figures that contain both caption and attr, especially if attrlink is present
• Doesn't respect figure sizing parameters like width
• If you click the figure it pops up in this weird way where it isn't even really zoomed in, which also breaks the link attribute; also works terribly if the figure is a vector diagram with a transparent background

So you've got my vote to get rid of it or make it optional.

[ahelwer]

Closing since there doesn't seem to be interest in merging this and it has been superseded