However... in that thread, the proposal I accidentally duplicated got shot down early and other alternatives were discussed.
I don't quite agree with the mentioned disadvantages of that proposal though:
Well but async is already doing "magic": It turns every return value into a promise, regardless of the function's contents. And await magically determines, if the passed expression actually is a Promise.
The proposed sync keyword (or await block in the other thread) would do the same but additionally await every expression inside the code block (sequentially in the order of expression evaluation).
Yeah, well "appetite" is something very subjective 
But I agree that in web programming await is always "important enough to being explicitly annotated" 
It's just for batch-style scripts that this would really make things more readably IMO. (For code intended for browsers it might even make sense to prohibit the proposed keyword via eslint.)
Consider node's fs.readFile vs fs.readFileSync for example: I've always found it quirky to have a second method that essentially does the same as the first, only that one returns a Promise and the other actually blocks the execution until the file has been read.
But I understand why they additionally introduced fs.readFileSync - for the same reason I'm proposing sync: To not have thousands of await keywords cluttering batch-style scripts.