Probably the closest is https://blog.rust-lang.org/2017/03/02/lang-ergonomics.html, which laid out the plans to do so. That being said, there wasn’t a single real document I can point you to: it was a label attached to a number of RFCs, and not really tracked as one thing. Some stuff that ended up landing under this banner was:
Non-lexical lifetimes
“Match ergonomics”
Implied lifetime bounds
The anonymous lifetime
The question mark operator
Async/await (this one is still in progress)
The removal of “extern crate”
... and some other things I’m sure I’ve forgotten. I also said “last year” but that blog post is from 2017, and that’s because it took a long time for RFCs to be created, accepted, implemented, and stabilized; a lot of this stuff landed in the latter half of last year, though some before then too.
Non-lexical lifetimes
“Match ergonomics”
Implied lifetime bounds
The anonymous lifetime
The question mark operator
Async/await (this one is still in progress)
The removal of “extern crate”
... and some other things I’m sure I’ve forgotten. I also said “last year” but that blog post is from 2017, and that’s because it took a long time for RFCs to be created, accepted, implemented, and stabilized; a lot of this stuff landed in the latter half of last year, though some before then too.