Function param_doc_entry_tokens 

pub(crate) fn param_doc_entry_tokens(
    cfg_attrs: &[Attribute],
    entry_ident: &Ident,
    placeholder: &str,
    several_ok: bool,
    suffix: &str,
    choices_ty: &Type,
) -> TokenStream

Emit the MX_MATCH_ARG_PARAM_DOCS static + its linkme registration.

suffix is the text the write pass puts after the rendered choice list, from ParamAttrs::choice_doc_suffix (“, or NULL for no choice” for an Option<T> param, #1473; the omission note for Missing<T>, #1551).