feat: better naming, typedef, wrap

[ThaUnknown]

I wanted to make something like this, found your library, decided to contribute

What this PR does:

• better naming: there's no need to name the async constructor async_constructor, if its already gonna be prefixed with async because you then have async async_constructor, just change it to constructor and we get async [constructor], miles easier to read
• added a wrap method, which uses the Proxy class, this is useful when u can't extend the async class, but I didn't test it against your asyncSuper thing
• added type definitions, so when you go to use the class or wrap function, instellisense will say "hey this constructor actually returns a promise", nice for type safety

[JenniferPylko]

thank you so much for the pr! i have a few notes, but overall it looks pretty good.

• in your typedef you still refer to the class as AsyncClass, was this intentional? i'm a bit rusty on typescript so i may just be misunderstanding
• i'm a bit wary of using a keyword as a variable name, even if it's ostensibly safe, but i do like the elegance of async [constructor]. to make it consistent with Super, i'd say let's name it Constructor.

some style things (i guess i should write up a style guide for contributing huh)

• please revert the whitespace change on the prototype generator function (function*( vs function * ()
• please use double quotes instead of single quotes
• please use snake case for non-exported, non-member variables
• please make wrap() an arrow function

i'll add some inline comments for a couple other things too, but thank you again!