It should be possible to distinguish between suggested and permissible parameters.
Background: It is much more common that templates have permissible parameters than suggested parameters. There are tools in use to detect incorrectly filled templates (use of non-existing params, omitting "required" params, non-numeric values for params typed "number", etc.).

More explanation: https://meta.wikimedia.org/wiki/Talk:WMDE_Technical_Wishes/Suggested_values_for_template_parameters#Marking_list_as_exhaustive