Lightbox disables using figure numbering

[ecodiv]

When lightbox is used in a page, figures are not numbered anymore (https://quarto.org/docs/authoring/cross-references.html).

Normally, the following will result in a caption below the figure that reads 'Figure 1: Elephant'.

![Elephant](elephant.png){#fig-elephant}

Using lightbox on that page will result in a caption reading 'Elephant'

[dragonstyle]

Note to self - this is occurring because the Lightbox filter is being run prior to crossrefs being resolved (and so figures aren't yet labeled and numbered). This is something that will perhaps be resolved by cross reference changes in Quarto 1.4, so I will revisit soon.