Support namespaced classes in <type> elements
Support namespaced classes in <type> elements

Currently, automatic linking to the documentation pages of namespaced
classes is supported in some elements (e.g. in `<classsynopsisinfo>`),
but not in `<type>` elements, which can be seen in the `CommonMark`
documentation[1].  We catch up on that.

[1] <https://www.php.net/manual/en/book.cmark.php>

php/phd,php/phd