Website breaks to missing extern definitions

[b-studios]

All examples on the website output

println$impl is not defined

The reason is that recently introduced inlining of extern definitions #350 will inline definitions like println

effekt/libraries/js/effekt.effekt

Lines 14 to 15 in 5dffce2

	extern io def println[R](value: R): Unit =
	"println$impl(${value})"

which in turn rely on extern includes or literals, such as

effekt/libraries/js/effekt.effekt

Line 8 in 5dffce2

extern include "effekt_builtins.js"

The problem now is that the website uses separate compiling, where the extern includes are only visible to the one module including them. Previously, println would simply close over the extern includes. But now, since we inline it, it cannot anymore.

Solution implemented in this hotfix

Inlining externs now differs (in JS) between separate and whole program compilation.

• When compiling whole-program, we inline extern defs.
• When compiling separate, we do not inline extern defs, since:

Drawback

• it adds complexity in the implementation of the javascript Transformer
• the hotfix looses some code-sharing with the direct-style backend, which currently is not used (neither in tests, nor on the website), since I moved some code into the "Monadic..." variants to easier control inlining.

[b-studios]

@dvdvgt once the PR is merged, could you update the website again and see whether this resolves the problem? (I clicked the CI button). The test I added should actually reproduce this error, though.