activate reanalyze's exception analysis for async/await

[zth]

Adding this enables reanalyze to do exception analysis when using rescript-fetch with the upcoming async/await feature in ReScript v10.1.

The exception analysis in question is shown here: https://forum.rescript-lang.org/t/ann-async-await-is-coming-to-rescript/3488/16

[glennsl]

Hi. Thanks for this, and sorry for the slow reply. I'm not that familiar with reanalyze, so I'm a bit confused as to what this actually does though. Is this signifying that fetch can raise an exception immediately, or only that it can do so through a promise, that is then raised when awaited? If the latter, how does it distinguish between immediate exceptions and async exceptions?

Also, why does this only apply to fetch, not get or send which are aliases for fetch, or even other async functions such as Response.json?