docs: Document navigation patterns and suppress diagnostics (#2232)

Extend navigation documentation with comprehensive best practices and
diagnostic suppression features:

- Add navigation configuration patterns (file, folder, nested toc)
- Document `suppress` field for docset.yml and toc.yml
- Explain DeepLinkingVirtualFile and FolderFileNameMismatch hints
- Describe anti-patterns each suppression addresses
- Add when-to-use guidance for each navigation pattern

The configure/content-set/navigation.md provides dry reference material
with complete YAML examples, while building-blocks/documentation-set-
navigation.md offers narrative-driven guidance with real-world scenarios
and progressive examples showing how to evolve documentation structure.

Author: Mpdreamz