8191632: Typos in comments due to duplicating words

Reviewed-by: alanb

src/java.base/share/classes/sun/net/www/MimeEntry.java

@@ -252,7 +252,7 @@ public class MimeEntry implements Cloneable {
             }
 
         case UNKNOWN:
-            // REMIND: What do do here?
+            // REMIND: What to do here?
             return null;
         }