Add: RPIT and RPITIT

[conqp]

Maybe the terms Return Position Impl Trait and Return Position Impl Trait In Trait are worth adding?

[Enet4]

Just maybe. :) It is worth emphasizing that this is not meant to be a glossary of technical terms in Rust, but for recurrent expressions which ended up having some level of acceptance in the developer community, often through memes, word of mouth, or other forms of social dissemination, be they technical or not. That does not exclude technical terms from taking part, but that should hopefully not be only reason for inclusion. For instance, HRTB (higher-ranked trait bounds) is a technical term, but what you find in rust-tropes is its mnemonic hearty boy. GATs is a technical term, but for a long time it was a distant mirage of a long-awaited feature for some until it finally happened, hence finding its place here (the pages predate its stabilization).

In this case, it is a matter of understanding whether those two concepts may end up being frequently said in Rust development circles.

[conqp]

I understand. I recently read them repeatedly on users.rust-lang.org, so I thought I might suggest it here.
Also those terms are not part of the official user docs. There they state:

Note: This is often called “impl Trait in return position”.

So the official abbreviation "should" be "ITIRP", but nobody calls it that.

Otoh RPITIT is mentioned only in the compiler's dev guide which the normal user may not usually read through.

[Enet4]

OK, if you make a pull request describing the current circumstances around those acronyms, I may be able to review it this month.