Fixes #24

[bhoov]

Boolean error is easily fixed by adding tostring

[jimjam-slam]

Thanks @bhoov! Looks like I forgot to cast a Boolean in a debugging statement. Not sure why it never caused a problem for me in testing, though 🤔 Will try to merge today!

[jimjam-slam]

Ah, I see; I didn't sufficiently test the single doc render code path (the Svelte compilation is handled y a separate script if you render as part of a project, and the code that locates the Svelte config is only in that script). I'll get both of these fixed up for you!

[jimjam-slam]

I've pushed an additional commit to this PR that additionally fixes #23 - the underlying problem is that when rendering a single doc, I wasn't making the path to the Rollup config available (#24 was a secondary error happening when trying to report the first). I'm just running checks, and then I'll merge both :)