Invalid 'http://asciidoctor.org' references

[abelsromero]

In docs, Javadocs, etc. there are several references to http://asciidoctor.org (around 30).

We should:

• Use only https references
• Update when necessary to point to the new docs site (https://docs.asciidoctor.org/)

For both:

• v3.0.0
• v2.5.9

[abelsromero]

Great, we can't assign multiple milestones to an issue 😞 I find GH goes to great lengths to not make life easier for maintainers.

[mojavelinux]

I tend to use tags for this instead.

[abelsromero]

I tend to use tags for this instead.

It seems indeed the only option.