How to Tag Entities/Keywords in ModernBert?

For identifying entities for ModernBert, what is the syntax? Is it something like the below?
What is best practice for embedding hierarchical documents with entities?

Travel-esque documement with entities:
```
search_document:
[TOPIC: Travel]
[SECTION: Europe]
[SUBSECTION: France]
[PARAGRAPH] The [KEYWORD: Eiffel Tower] is a must-visit landmark in Paris.
[SUBSECTION: Italy]
[PARAGRAPH] The Colosseum in Rome is a symbol of ancient history.
[SECTION: North America]
[SUBSECTION: USA]
[PARAGRAPH] The Statue of Liberty is a famous symbol of freedom.
```

No files, tests, or entry points are identified in the issue. Start by reviewing the repository's ModernBERT usage guidance and determine whether entity tagging or hierarchical document embedding syntax is supported. Done means providing a clear, documented answer to both questions, including any applicable examples or limitations.

Written by the indexing model from the issue text.