Add Argument.BOOLEAN

SpigotCore_Main/src/de/steamwar/command/Argument.java

@@ -32,7 +32,7 @@ import java.util.stream.Collectors;
 
 public class Argument<T> {
 
-    public static final Argument<Boolean> BOOLEAN = new Argument<>(ArgumentType.BOOLEAN, bool -> true);
+    public static final Argument<Boolean> BOOLEAN = new Argument<>(ArgumentType.BOOLEAN, bool -> true, "true", "false");
     public static final Argument<Integer> INT = new Argument<>(ArgumentType.INT, integer -> true);
     public static final Argument<Long> LONG = new Argument<>(ArgumentType.LONG, l -> true);
     public static final Argument<Float> FLOAT = new Argument<>(ArgumentType.FLOAT, f -> true);
@@ -49,6 +49,10 @@ public class Argument<T> {
         this(argumentType, constraint, o -> o, () -> tabCompletes);
     }
 
+    public Argument(ArgumentType<T> argumentType, Predicate<T> constraint, Supplier<String[]> tabCompletes) {
+        this(argumentType, constraint, o -> o, tabCompletes);
+    }
+
     public <M> Argument(ArgumentType<T> argumentType, Predicate<T> constraint, Function<T, M> valueMapper, Supplier<String[]> tabCompletes) {
         this.argumentType = argumentType;
         this.constraint = constraint;