Article reference can collide with top-level symbol

[d-ronnqvist]

Description

If a catalog is named the same as the module and an article is named the same as a top-level symbol, then the article and the symbol both get the same ResolvedTopicReferences and DocC only emits a page for the article.

rdar://109177620

Checklist

• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue.

Expected Behavior

The ResolvedTopicReferences should contain disambiguation so that nothing every page has a unique reference. Both pages should be emitted.

Actual behavior

Only the article page is emitted.

Steps To Reproduce

1. Create a DocC catalog with the same name as the module it documents
2. Create an article—not a documentation extension—and name it the same as one of the top-level symbols in the module
3. Curate the article
4. Build documentation and inspect the content of the output. There won't be a json file for the symbol.

Swift-DocC Version Information

At least a few versions back (5.5)

Swift Compiler Version Information

No response

[tayloraswift]

note this currently affects swift-markdown at 0.3 (BlockMarkup, InlineMarkup)

see: apple/swift-markdown#158