Strip marker exposed in {{DEFAULTSORT:}}

{{DEFAULTSORT:Foo, <nowiki />Bar}} -> pp_value == "Foo, UNIQ--nowiki-00000001-QINUBar" (or any other number as it is changeable)

Used by construction:
{{DEFAULTSORT:{{{sortkey|{{#if:{{{surname|}}}|{{{surname}}}, <nowiki/>}}{{{name}}}}}}}}