Nested lists with paragraphs are incorrectly rendered and cause NPEs

I think I understand what happens. Lists that are wrapped in other list items are not "block handlers" as they don't require, e.g., a nested document tag. However, as, when the inner list starts, we are directly inside the created group syntax, we are not in a block context when the paragraph is opened. Therefore, the paragraph tag handler doesn't trigger the opening of a nested document. In the InternalWikiScannerContext the opening of the paragraph then closes the list before opening the paragraph.

I think the correct thing to do is to consider lists as block handlers if a nested document tag was opened. This fixes this example for me. I'll open a pull request. I still need to check the null pointer if that has been fixed in the meantime as I didn't reproduce it.