intra-doc links: Links with unexpected characters are silently ignored

[dylni]

Intra-doc links with unexpected characters are ignored here:

rust/src/librustdoc/passes/collect_intra_doc_links.rs

Lines 931 to 933 in 78a0894

	if path_str.contains(|ch: char| !(ch.is_alphanumeric() || ch == ':' || ch == '_')) {
	return;
	}

However, it would be better if they caused a warning with --display-doctest-warnings. Developers might expect [`&[String]`] to link to the slice primitive, but that link would be ignored without a warning.

cc @jyn514
cc #76106 (comment)

[camelid]

FWIW, I think this is less of an issue now, since more characters are allowed in intra-doc links, and thus not ignored. Also, IIRC --display-warnings has now been renamed to --display-doctest-warnings, so that flag shouldn't be used here. Maybe we could add another lint or something? But like I said, it's less of an issue now.

[dylni]

@camelid Thanks, I updated the option name. However, I am still not seeing a warning for [`&[String]`], which was my primary concern. It would be ideal if bracketed text could either be properly linked or give a warning in all cases.