This guide only applies if you have no Module Hilite field in a particular module such as the CB Random Users module. Most modules have it already but in the rare occasion that it doesn't, this guide will help.
This has nothing to do with templateDetails.xml at all as that is purely for template use only. The only files we are concerned with are mod_"module name".xml.
If the module has no parameters, it will not have <params>, <param>, or </params>. In that rare case you would have to add them all. The example I gave was for adding a Module Hilite field<param name="moduleclass_sfx" type="text" default="" label="Module Class Suffix" description="A suffix to be applied to the css class of the module (table.moduletable), this allows individual module styling"/>
If there are no other params, wrap that code to emulate<params>
<param name="moduleclass_sfx" type="text" default="" label="Module Class Suffix" description="A suffix to be applied to the css class of the module (table.moduletable), this allows individual module styling"/>
</params>