Rename to Promise

[trowski]

While this issue was discussed in #4, Awaitable was a compromise to (mostly my) objections to using the name Promise, avoiding confusion from the standard interface not having a then() method. However, after using and discussing awaitables for the past few months, it has become clear that Promise is a more ubiquitous term. Thus I propose we change Awaitable to Promise.

I still feel there will be some confusion over not having a then() method, but this confusion can be solved with highlighted documentation.

[trowski]

Ping @assertchris @WyriHaximus @AndrewCarterUK @rdlowrey @jsor @sagebind @mbonneau @joelwurtz

Do any of you have opinions on this rename to Promise?

[WyriHaximus]

I'm in favour 👍 and with some extra documentation we can make perfectly clear why we want with when instead of then

[bwoebi]

@WyriHaximus Is https://github.com/async-interop/awaitable/blob/master/META.md#choice-of-when not clear enough yet?

[WyriHaximus]

@bwoebi it is, and was referring to that piece of documentation as something extra on top of the normal documentation. Could have done that better though 🤐

[jsor]

I don't mind a rename. I'm pretty sure though that there will be a lot of confusion with standard Promises/Thenables event if it's documented.

[joelwurtz]

As an user i found Awaitable to be better, prior to see this interface i exclusively used Promise and the traditional flow of chaining them without thinking to more about the implementation.

When i see this spec, i was wondering why it was not called Promise so i look more on the implementation and certainly ask a bunch of stupid questions.

However that was the name Awaitable that begin this, having this class called Promise would, certainly, have confuse me even more...