Changed body font to Source Serif Pro.

I was playing around with serif fonts a bit and, landing on Source Serif, I found something that fit with my style in a way that no others did.

Visually quite a big change, the previous body font was the very modern Inter, a serif font, which I have kept for eg. titles for now.

Just noticed that Source Serif Pro isn’t handling left-single-smart-quotes correctly when they’re in italics, instead falling back to the right-quote/apostrophe. A pretty niche case, but I care about those little details. I’ll have to investigate whether it’s just missing from the font altogether, or if I inadvertently removed it when sub-setting it for my uses.

’example’

(If the above is no longer wrong, it’s because I’ve fixed the issue.)