Function describe_firstparty_symbol 

pub(crate) fn describe_firstparty_symbol(name: &str) -> Option<String>

Describe a symbol declared in the embedded first-party sources — the bynk and bynk.cloudflare adapters and the bynk.list/bynk.map/bynk.string stdlib. Hover and completion-doc resolution otherwise walk only the project’s files (walk_bynk_files), so stdlib/surface symbols had no surfaced signature or doc; this is the fallback after the project scan. Any --- doc block on a first-party declaration rides along (via describe_fn/describe_type/…), once the sources carry one.