code style fixes

Author: zefir-git

src/main/java/pro/cloudnode/smp/smpcore/Permission.java

@@ -160,5 +160,5 @@ public final class Permission {
     /**
      * Bypass death ban.
      */
-    public static @NotNull String DEATHBAN_BYPASS = "smpcore.deathban.bypass";
+    public static final @NotNull String DEATHBAN_BYPASS = "smpcore.deathban.bypass";
 }

src/main/java/pro/cloudnode/smp/smpcore/command/BanCommand.java

@@ -15,10 +15,10 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Date;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 public final class BanCommand extends Command {
     private static void ban(
@@ -62,7 +62,7 @@ private static void ban(
         }
 
         final Member main = targetMember.get().altOwner().orElse(targetMember.get());
-        final HashSet<Member> alts = main.getAlts();
+        final Set<Member> alts = main.getAlts();
 
         ban(main.player(), reason, banExpiry, banSource);
         final List<Member> bannedMembers = new ArrayList<>();