Support phpdoc tags like @template (and others)

We'd need to investigate first what the PHP parsing library (https://github.com/nikic/PHP-Parser) returns, and then work on a solution based on that.

Commenting because this might be kinda annoying if we want to get stuff into core.

Wonder how this should actually look in that page. The parsing is probably not that hard. But we might need: https://github.com/phpstan/phpdoc-parser which adds support for a lot of extra types? (see https://github.com/phpstan/phpdoc-parser/blob/fcaefacf2d5c417e928405b71b...)

Most important though, how does the doc page need to look. Not sure about that. But if we have a direction on that adding is should be easy.

Thanks for that link. It's really useful.

Other tags worth nothing (from 🐛 When parsing @coverDefaultClass, a link to the documentation class is provided, but the link is rendered as plain text Fixed ): @coversDefaultClass @group @internal