Use the single-letter icon for namespace symbols in navigator

[mportiz08]

Bug/issue #, if applicable: 120780967

Summary

Updates configuration so that pages for C++ "namespace" symbols are rendered with a single-letter "N" icon in the navigator sidebar instead of a generic "article" icon.

Example

Dependencies

swiftlang/swift-docc#817

Testing

Steps:

1. Checkout this branch of swift-docc-render and build it with npm run build
2. Checkout my branch of swift-docc from Use a more detailed page type for C++ namespaces in navigator index swift-docc#817 and build it with swift build
3. Preview the example C++ doc catalog with DOCC_HTML_DIR=/path/to/swift-docc-render/dist swift run docc preview Tests/SwiftDocCTests/Test\ Bundles/CxxSymbols.docc
4. Open http://localhost:8080/documentation/cxxsymbols and verify that the Foo namespace in the navigator is using the "N" icon

Checklist

Make sure you check off the following items. If they cannot be completed, provide a reason.

• Added tests (unit test for icon mappings are dynamically generated)
• Ran npm test, and it succeeded
• Updated documentation if necessary

\cc @daniel-grumberg

[hqhhuang]

Looks good!
I find it a bit confusing that a page tagged with the TechnologyIcon has article style content instead of symbol style content though. Why don't we use a symbol icon with the letter N to represent namespace symbols?

[mportiz08]

Looks good! I find it a bit confusing that a page tagged with the TechnologyIcon has article style content instead of symbol style content though. Why don't we use a symbol icon with the letter N to represent namespace symbols?

While a C++ namespace is technically categorized as a symbol by DocC, it conceptually represents a grouping of other symbols, most similar to a module in Swift, which we render with the generic "technology" icon.

[mportiz08]

@daniel-grumberg suggested using the "N" icon as well, so I've changed it to that

[mportiz08]

@swift-ci test

[eango]

Tested and looking good; thanks @mportiz08