RSS-related fixes

[maleadt]

No description provided.

[maleadt]

I see you've caught some of these fixes already, I'll remove them here.

[tlienart]

Thanks a lot for this, adding some thoughts for the eventual completion of the work on my side:

• full content has an ambiguity for {{..}} function in terms of how they should be inserted
• the description should be plain text if there's content (though actually it looks like no one knows), there's no function to go from markdown to plain text at the moment

[maleadt]

FWIW (maybe relevant as part of the bigger picture), I'm also happy to host my own version of an RSS template that suits my needs. With Hugo, it was convenient to do so as the RSS feed was just another template: https://github.com/JuliaGPU/juliagpu.org/blob/ce6a64b1f33e7eb9c9473705e73f1afa7ac7ee65/themes/vanilla-bootstrap/layouts/_default/rss.xml. As it looks like Franklin already has some sort of templating engine for the HTML layout, could that be used for e.g. RSS and sitemap generation too (instead of the custom generators)?

[tlienart]

This is a very good point and I had not thought about it, thanks! I need to mull over this a bit and hopefully something nice will come out 😄

Edit: to keep track, MichaelHatherly/CommonMark.jl#18

[tlienart]

closing this as changes are now pending on #799, thanks Tim