Auto merge of #18294 - Giga-Bowser:master, r=Veykril

Add wrap/unwrap return type in Option

I pretty much just copied over the code and tests for wrapping/unwrapping return types in `Result` and then did a bunch of find and replace changes.

I handled unwrapping statements returning `None` by just replacing `None` with the unit type, but I'm open to suggestions for more intuitive behavior here.

Author: bors