Make Witchcraft.Chain.do_notation respect chainer

[florius0]

Summary

This PR fixes Witchcraft.Chain.do_notation/2.
Previously it ignored second argument assuming any chainer is Witchcraft.Chain.chain/2.

However, there is a call of do_notation/2 across Witchcraft codebase in which chainer other then chain/2 is passed:

witchcraft/lib/witchcraft/monad.ex

Lines 284 to 287 in 6c61c3e

	defmacro async(sample, do: input) do
	returnized = desugar_return(input, sample)
	Witchcraft.Chain.do_notation(returnized, &Witchcraft.Monad.async_bind/2)
	end

Test plan (required)

mix test should be enough

Closing issues

Fixes #108

After Merge

• Does this change invalidate any docs or tutorials? If so ensure the changes needed are either made or recorded
• Does this change require a release to be made? Is so please create and deploy the release

[florius0]

Moreover, the fact mention above can be proved as follows.

Running this snippet before would've returned [links: []], which points that no process were spawn_link'ed to shell process (if the snippet is run from shell).

async [] do
  let a = 1
  let b = 2
  
  return a + b
  
  return Process.info(self, :links)
end

Now, it shows that the process is indeed linked: [links: [#PID<0.238.0>]]

[florius0]

@QuinnWilton could you take a look?

[cognivore]

Wow, thanks for the PR, @florius0 I'll review it shortly and incorporate into doma-engineering fork and provide feedback here + at fission discord. 💙 💛