Nested lists - Lists can directly contain another list

[mato7d5]

These changes add support for nested lists: List into List. The specs enables insert on List into another List and I needed this behavior in our project. Currently the List can be nested into another list via ListItem which adds extra tags (L -> LI -> L). This enables L -> L.

[iText-CI]

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[vitali-pr]

Hi @mato7d5 ,
Thank you for your contribution!

Would you mind signing the Contributor License Agreement?
The details are available at https://itextpdf.com/en/how-buy/legal/itext-contributor-license-agreement
We need it in order to be able to merge your PR.

Next to that, it would be great if you add some tests into itext.layout.tests project.

[mato7d5]

Hi @vitali-pr

done - signed and sent CLA + I've added the unit test.

[vitali-pr]

Hi @mato7d5 ,
I had a closer look at your PR and have some questions/remarks on the use case.

1. We follow PDF/UA spec by default when it comes to tagging. And it says "Individual list items shall be specified by LI tags. Lbl and LBody tags may be included.". It does not directly violates your desire though.
2. What is the purpose of having L inside L? I think such structure is ambiguous for screen readers if inner L does not belong to any LI.
3. We have quite wide abilities to customize tags. Could you attach a sample document with the desired tag structure? I could come up with some solution for that based on the current API.

[vitali-pr]

Is it somewhat you need?
nestedListTest01.pdf