Auto merge of #104417 - mejrs:mir_build, r=davidtwco

Migrate rustc_mir_build diagnostics

Rebases rust-lang/rust#100854

~~The remaining issue is how to better resolve rust-lang/rust@72bea68af4ee2a41c44998916f6a789163f12e7d~~

~~The diagnostic macros seems to generate a broken diagnostic, and I couldn't figure out how to manually format the fluent message, so I hardcoded the format string for now. I'd like pointers to a better fix for this.~~

Also, I'm not 100% sure I didn't mess up a rebase somewhere 🙂

r? `@davidtwco`

Author: bors