Merge sync and async functions into one using SmartCoro

[friendlyanon]

Hey, I would like to hear your opinion on this before I dive into #27
The reason why I merged sync and async functions is because the logic was duplicated, which can be error prone. I wanted to get this out of the way before attempting #27 because whatever gets added would have had to be duplicated as well.

[sindresorhus]

This is clever, but IMHO a bit too clever. You are trading less duplication for complication and making it less readable. I don’t think duplication is that bad, especially not when the code is almost the same (just added await keyword) and well tested.

[friendlyanon]

I have a discord bot of a modest size that makes use of this generator wrapper (with additional features) and I find it greatly reduced complexity to allow a more declarative style of writing code. I can see this being overkill for this utility though.

Thank you for the response, I'll proceed accordingly.