((closed|text=))
or
((closed|Deleted (or some other summary), without a signature.|text=))
The template will automatically detect if the discussion is archived to a standard archive, and adjust the text accordingly.
Avoid using a summary with bold markup inside other markup. For example, do not do this:
((closed|Here is my <sub>subscripted '''Bold'''</sub> summary|Text))
However, these are OK:
((closed|Here is my <sub>subscripted ''Italic''</sub> summary|Text))
((closed|Here is my '''Bold''' summary|Text))
((closed|Here is my '''Bold <sub>subscripted</sub>''' summary|Text))