Function workspace_symbols 

pub fn workspace_symbols<'a>(
    index: &'a ProjectIndex,
    query: &str,
) -> Vec<(&'a SymbolKey, &'a SiteRef)>

v0.26 rider (ADR 0055): workspace/symbol — every index definition whose name contains the query, case-insensitive (an empty query lists all), sorted by (name, unit) for a stable order.