[css-text] Acknowledgements updated

Author: kojiishi

css-text/Overview.bs

@@ -2590,7 +2590,7 @@ Acknowledgements</h2>
   Laurie Anna Edlund, Ben Errez, Yaniv Feinberg, Arye Gittelman, Ian
   Hickson, Martin Heijdra, Richard Ishida, Masayasu Ishikawa,
   Michael Jochimsen, Eric LeVine, Ambrose Li, Håkon Wium Lie, Chris Lilley,
-  Ken Lunde, Nat McCully, Shinyu Murakami, Paul Nelson, Chris Pratley, Marcin Sawicki,
+  Ken Lunde, Nat McCully, IM Mincheol, Shinyu Murakami, Paul Nelson, Chris Pratley, Marcin Sawicki,
   Arnold Schrijver, Rahul Sonnad, Alan Stearns, Michel Suignard, Takao Suzuki,
   Frank Tang, Chris Thrasher, Etan Wexler, Chris Wilson, Masafumi Yabe
   and Steve Zilles.