Function cgroup_limits_cell 

pub fn cgroup_limits_cell(
    baseline: Option<(Option<u64>, u64)>,
    candidate: Option<(Option<u64>, u64)>,
) -> String

Render a baseline → candidate cell for cpu.max (quota, period) pairs. When both pairs are equal, renders once via format_cpu_max; otherwise renders as <a> → <b>. Mirrors cgroup_optional_limit_cell’s equality-collapse policy.