Add references to LocaleCanonicalizer

[sffc]

Follow-up from #5296

I couldn't linkify them because of the dependency order

[robertbastian]

Suggested change

	/// No subtag validation or alias resolution is performed; use `LocaleCanonicalizer`.
	/// For validation and canonicalization, see `LocaleCanonicalizer`.

[sffc]

I think it is useful to explicitly call out that this function does not perform validation and canonicalization. If you expand the file, there is a list of three levels of conformance, and this function performs one but not the other two.

It is still a bit confusing that the previous line references "bogus subtags" without any definition of what "bogus" means.

[sffc]

@zbraniecki Do you have a wording suggestion?

[zbraniecki]

I don't like bogus here - it seems underdefined.
Suggestion:

/// Any syntactically invalid subtags will cause the parsing to fail with an error.
/// This operation normalizes syntax only. No legacy subtag replacements is performed.
/// For data validation and subtag canonicalization, see `LocaleCanonicalizer`.

[sffc]

OK I applied that suggestion. Look good to merge?

[robertbastian]

Why "data validation" instead of "validation"? Why "subtag canonicalization" instead of "canonicalization? The list above doesn't say "well-formed", "data-valid", and "subtag-canonical".

[zbraniecki]

I'm ok with changing it to:

This operation normalizes syntax to well-formed. No legacy subtag replacements is performed.
For validation and canonicalization, see LocaleCanonicalizer.

[sffc]

Done.

[robertbastian]

nb: I would even shorten it to

This operation normalizes syntax to be well-formed. For validation and canonicalization, see LocaleCanonicalizer.

because it follows from the definition above that "normalizing syntax to be well-formed" does just that, and subtag replacement is part of canonicalization.