Remove unneeded ISOdia entity

man/en/dselect.8.sgml

@@ -1,7 +1,4 @@
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN" [
-  <!ENTITY % ISOdia PUBLIC "ISO 8879:1986//ENTITIES Diacritical Marks//EN">
-  %ISOdia;
-]>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN">
 
 <refentry id="dselect.8">
   <refmeta>