Function bounds_from_generic_clauses 

fn bounds_from_generic_clauses<'tcx>(
    tcx: TyCtxt<'tcx>,
    clauses: impl IntoIterator<Item = (Clause<'tcx>, Span)>,
    assoc: AssocItem,
) -> (String, String)

Re-sugar ty::GenericClauses in a way suitable to be used in structured suggestions.