#[doc(alias)]'s doc: say that ASCII spaces are allowed

[ShE3py]

PR #77570 allowed ASCII spaces in doc aliases, but the documentation wasn't updated to say so.

The code checking the aliases:

rust/compiler/rustc_passes/src/check_attr.rs

Lines 693 to 704 in 7fdefb8

	let doc_alias_str = doc_alias.as_str();
	if let Some(c) = doc_alias_str
	.chars()
	.find(|&c| c == '"' || c == '\'' || (c.is_whitespace() && c != ' '))
	{
	tcx.dcx().emit_err(errors::DocAliasBadChar { span, attr_str, char_: c });
	return false;
	}
	if doc_alias_str.starts_with(' ') || doc_alias_str.ends_with(' ') {
	tcx.dcx().emit_err(errors::DocAliasStartEnd { span, attr_str });
	return false;
	}

@rustbot label +A-docs

[rustbot]

r? @fmease

rustbot has assigned @fmease.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[fmease]

Thanks all!
@bors r+ rollup

[bors]

📌 Commit ec662e7 has been approved by fmease

It is now in the queue for this repository.