Rustdoc reports `broken-intra-doc-links` for Github markdown `[!IMPORTANT]`-type blockquotes

[Qix-]

I tried this code:

#![doc = include_str!("../README.md")]

> [!IMPORTANT]
> This is an important message

I expected to see this happen: Rustdoc at least generating documentation (perhaps not with specialized support for the [!FOO] syntax, but at least not error)

Instead, this happened: With env RUSTFLAGS="-D warnings", rustdoc errored with unresolved link to '!NOTICE'

Meta

rustc --version --verbose:

rustc 1.89.0-nightly (6f6971078 2025-05-28)
binary: rustc
commit-hash: 6f69710780d579b180ab38da4c1384d630f7bd31
commit-date: 2025-05-28
host: x86_64-unknown-linux-gnu
release: 1.89.0-nightly
LLVM version: 20.1.5

rustdoc --version --verbose:

rustdoc 1.89.0-nightly (6f6971078 2025-05-28)
binary: rustdoc
commit-hash: 6f69710780d579b180ab38da4c1384d630f7bd31
commit-date: 2025-05-28
host: x86_64-unknown-linux-gnu
release: 1.89.0-nightly
LLVM version: 20.1.5

[lolbinarycat]

We actually already suppress this lint on shortcut-style links specifically in some cases, so i guess it wouldn't be the worst to suppress them in a few other cases, i guess?

[Qix-]

Yeah, especially given that there are a finite number of them: https://github.com/orgs/community/discussions/16925

If you point me in the right direction as to where to look for this, I'm happy to submit a PR :)

[lolbinarycat]

it's in preprocess_link in passes/collect_intra_doc_links.rs.

we could probably just look for the ! at the start for shortcut links specifically (collapsed links and all the other ones are pretty unambiguous)

[lolbinarycat]

This should be pretty easy to implement once #132748 gets merged.