This extension to the typical `<>` Markdown autolink syntax allows
HTTP(S) links to be recognized in normal text without being delimited by
`<>`. This is the most natural way to write links in text, so it makes
sense to support it and allow documentation comments to be written in a
more natural way.
Closes#19265
This commit implements support for Markdown autolinks delimited by angle
brackets. The precise syntax accepted is documented in the doc comment
of `markdown.zig`.