AsciiDoc: Fix highlighting of include directive

Summary:
The include directive is always processed, even when within verbatim or passthrough blocks.
It should therefore be highlighted in these cases too.

• Fix the highlighting definition asciidoc.xml.
• Adjust and improve test file asciidoc.adoc.
• Update created .fold, .html and .ref files.

Reviewers: Framework: Syntax Highlighting, dhaumann

Reviewed By: Framework: Syntax Highlighting, dhaumann

Subscribers: kwrite-devel, kde-frameworks-devel

Tags: Framework: Syntax Highlighting, Kate, Frameworks

Differential Revision: https://phabricator.kde.org/D18617