Remove duplicate name from list of acknowledgments

Reported-by: m.zhilin@postgrespro.ru

Author: petere

doc/src/sgml/release-17.sgml

@@ -3498,7 +3498,6 @@ Author: Alexander Korotkov <akorotkov@postgresql.org>
     <member>Michal Bartak</member>
     <member>Michal Kleczek</member>
     <member>Mikhail Gribkov</member>
-    <member>Mikhail Zhilin</member>
     <member>Mingli Zhang</member>
     <member>Miroslav Bendik</member>
     <member>Mitsuru Hinata</member>