[4.0]mod_related strings (#31639)

Remove an unused string.

Code review

language/en-GB/mod_related_items.ini

@@ -5,7 +5,6 @@
 
 MOD_RELATED_FIELD_MAX_DESC="The maximum number of related articles to display (default is 5)."
 MOD_RELATED_FIELD_MAX_LABEL="Maximum Articles"
-MOD_RELATED_FIELD_SHOWDATE_DESC="Show or hide date."
 MOD_RELATED_FIELD_SHOWDATE_LABEL="Date"
 MOD_RELATED_ITEMS="Articles - Related"
 MOD_RELATED_XML_DESCRIPTION="This module displays other Articles that are related to the one being viewed. These relations are established by the Keywords. <br>All the keywords of the current Article are searched against all the keywords of all other published Articles. For example, you may have an Article on &quot;Breeding Parrots&quot; and another on &quot;Hand Raising Black Cockatoos&quot;. If you include the keyword &quot;parrot&quot; in both Articles, then the Related Items Module will list the &quot;Breeding Parrots&quot; Article when viewing &quot;Hand Raising Black Cockatoos&quot; and vice-versa."