Function code_lenses 

pub fn code_lenses<'a>(
    index: &'a ProjectIndex,
    path: &Path,
) -> Vec<(&'a SiteRef, &'a [SiteRef])>

v0.33 (ADR 0066): codeLens — one reference-count lens per top-level definition in path, as (def site, reference sites). The count is refs.len(); the reference sites feed the showReferences action. Sorted by definition position (a stable, top-to-bottom lens order).