Fix bug in rustdoc -Whelp

[jyn514]

Previously, this printed the debugging options, not the lint options,
and only handled -Whelp, not -A/-D/-F.

This also fixes a few other misc issues:

• Fix // check-stdout for UI tests; previously it only worked for run-fail and compile-fail tests
• Add lint headers for tool lints, not just builtin lints

#98533 (comment)

r? @GuillaumeGomez

[jyn514]

before, // check-stdout was broken and did nothing for UI tests

[jyn514]

this can't just be register_plugins() because that ends up trying to parse the source file, which fails because it's an empty string. this code is taken from

rust/compiler/rustc_driver/src/lib.rs

Lines 249 to 263 in e1b6f16

	if sopts.describe_lints{
	letmut lint_store = rustc_lint::new_lint_store(
	sopts.debugging_opts.no_interleave_lints,
	compiler.session().unstable_options(),
	);
	let registered_lints =
	ifletSome(register_lints) = compiler.register_lints(){
	register_lints(compiler.session(),&mut lint_store);
	true
	}else{
	false
	};
	describe_lints(compiler.session(),&lint_store, registered_lints);
	return;
	}

[jyn514]

this ended up fixing my original complaint in #98533 (comment) :)

[GuillaumeGomez]

Just to be sure: there are other UI tests that check the output you removed?

[jyn514]

Yes, you can see them in the diff: src/test/rustdoc-ui/issue-83883-describe-lints.rs
The run-make test did the same thing and couldn't be blessed, so it would have to be manually updated on each new lint.

[GuillaumeGomez]

Thanks!

@bors r+ rollup

[bors]

📌 Commit 17da4e0 has been approved by GuillaumeGomez