non sysroot macros re-exported in std have broken source links

[lolbinarycat]

Location

https://doc.rust-lang.org/nightly/std/arch/macro.is_arm_feature_detected.html

Summary

Source link actually just brings you to the crate README, seems like a broken link template.

[lolbinarycat]

also see rust-lang/stdarch#1799

[lolbinarycat]

I think the proper way to do this would be to make cargo aware of --extern-root-html-url, and allow it to interpolate in the actual version of crates that are being used.

[Amanieu]

The proper solution here is for the std_detect docs to be published on doc.rust-lang.org. The docs on docs.rs are outdated because we don't use std_detect from crates.io and the last published version is very out of date.

[lolbinarycat]

It would be nice if old versions of the stdlib docs also linked to the correct version on crates.io, for posterity, though that may be somewhat excessive given the moderate effort this would require.

[Amanieu]

The last release of std_detect is from 2019, we've always used the version from the sysroot.

[lolbinarycat]

Is there a reason we need to continue using --extern-html-root-url instead of including std_detect docs in the bundled documentation with a disclaimer like we do with test?

[Amanieu]

There is no reason. We should just do that.

[Amanieu]

I'm not exactly sure what steps need to be taken to get std_detect docs uploaded to doc.rust-lang.org, but once that's done then we just need to revert #131067.