Function build_port_column 

pub(crate) fn build_port_column(
    title: &str,
    names: &[String],
    prefix: &str,
    lookup: &mut HashMap<String, String>,
    default_port: &mut Option<String>,
    target_len: usize,
    align: TextAlign,
) -> TableNode

Keep input/output rows aligned and generate stable port identifiers.