embed svg instead of png for plot

[tpapp]

I would like

# # Experiment with Literate

using PGFPlotsX
Plot(Table(1:10, 1:10))

rendered with Literate.markdown("index.jl", ".", flavor = Literate.CommonMarkFlavor(), execute = true) to embed the plot as svg instead of png.

Looking at the source, this seems to be hardcoded. Ok if I make a PR to customize this, or is there an easier way?

[fredrikekre]

Sure, that would be fine. I just didn't know if there was a common enough way to embed svg in markdown.

[tpapp]

Cf #126.