Use guides to parse and render markdown

[jaapio]

This is an effort to remove the static website generator project as a dependency. In it's current state guides-markdown does not support all we need to replace the markdown rendering, so I'm working on that while fixing this project as well.

• 🐛 Nested inline nodes are not supported phpDocumentor/guides#1160

With linkable headings:

And nice code blocks like the docs have:

[SenseException]

Nice. I'll test this when I get the time. Can you please add a test for the newly introduced class?

[SenseException]

Looks great. Code snippets look better now and headlines have anchors. I found a few anomalies in the rendering of markdown pages though:

Ordered and unordered lists gaps

Because of a <p> tag that is rendered with the <li> and <ol> ones do lists have a gap of a paragraph for all markdown pages.

(https://www.doctrine-project.org/2016/01/05/dbal-2-5-4-and-2-4-5.html)

Missing links and anchor

In at least one case aren't the links in a headline rendered and the anchor can't be used. The anchor also looks wrong being dark and bigger than on other pages. I assume this might have something to do with the brackets in the headline.

(https://www.doctrine-project.org/2021/11/26/dbal-3.2.0.html)

[jaapio]

I checked the headlines in the blogpost that look malformed, and those are actaully links within the headline. And that makes it look very strange.

## Support for `psr/log` ([#4967](https://github.com/doctrine/dbal/pull/4967))

As the headline is rendered as a link, and includes a link.... yeah that's where things get really ugly...
Honestly I don't know how to solve that, do you want me to update those posts? And transform the link to the issue to a link directly below the headline?

[jaapio]

The issue with the paragraphs is covered in phpDocumentor/guides#1168

[jaapio]

Fixed the list:

[jaapio]

Although I do agree with you tests are very much needed the added class in this PR is very hard to test. Basically we just glue some external parts together. Adding a test would be nothing more than a very complicated mock and it will basically test nothing as the parser is an external project and the noderenderer is as well.

The rest will be covered by static analysis.

[SenseException]

do you want me to update those posts? And transform the link to the issue to a link directly below the headline?

Yes, that would probably be the best.

Adding a test would be nothing more than a very complicated mock

There are also functional tests, like in tests/FunctionalTest.php where a service can be used. The content for the rendering itself can be controlled with the injected Doctrine\StaticWebsiteGenerator\SourceFile\SourceFile object.