I've just marked Documentation curation - FoundationEssentials #2209 as ready for review. This pull request is the first big step to hosting swift-foundation documentation on https://docs.swift.org.
The PR adds 200+ .md files to the .docc documentation catalog. This provides the browsable topic hierarchy, so you can drill down through topics like FoundationEssentials > Dates and Times > Date representations > Date > Getting time intervals > timeIntervalSince(_:).
The PR also edits DocC-formatted documentation comments in the source to remove references to Apple-only types and functionality, and to repair symbol links (or replace them with code voice if necessary, which sometimes happens with references between FoundationEssentials and FoundationInternationalization, which are two separate modules in swift-foundation, and therefore can't link with the DocC double-backtick syntax).
Because the PR is big, the most practical way to review it may be to browse the preview site, which represents what these docs will look like when hosted on swift.org.
This PR covers the FoundationEssentials module. After it merges, we'll do a separate PR for FoundationInternationlization. When both have merged, we should be ready to host the swift-foundation docs on https://docs.swift.org.
Thanks in advance for your feedback!