RFC: Remove autolink support ✅

[johno]

Autolinks are a feature in Markdown that allow you to wrap a url in angle brackets: <https://mdxjs.com>. Currently, in v1, we support them but with the parser changes in #1039 they've been dropped.

This comes at a cost of breaking perfect interoperability with Markdown, but perhaps it makes sense because it makes < a clearer boundary for JSX syntax, which may be more clear to users. It might also be more confusing.

This issue is for discussing the potential implications of removing autolink syntax.

[wooorm]

TL;DR (from here) on why I think they’re a bad idea to support:

The reason for this change is because whether something is an element (whether HTML or JSX) or an autolink is ambiguous (Markdown normally treats <svg:rect>, <xml:lang/>, or <svg:circle{...props}> as links).

[wooorm]

Extra--while this is a bit far away for most folks except for John and me who have tried the new parsing out--we now have error messages that point to exactly where a typo/problem is, with a reason, and what was expected. That greatly improves developer experience. If we relax around things that might be a link, errors will start slipping through unnoticed.