refactor: remove unuse code

.inscode

-run = "javac design_pattern_23/singleton/Sington.java && java design_pattern_23.singleton.Sington"
+run = "javac Main.java && java Main"
 language = "java"
 
 [debugger]

design_pattern_23/singleton/Sington.java

-package design_pattern_23.singleton; 
-
-/**
-* 饿汉式
-*/
-public class Sington {
-
-    private static Sington INSTANCE = new Sington();
-
-    private Sington(){}
-
-    public static Sington getInstance(){
-        return INSTANCE;    
-    }
-
-    public String print(String info){
-        System.out.println(info + " : Instance="+this);
-        return "";
-    }
-
-
-    public static void main(String[] args){
-        Sington.getInstance().print("1");
-        Sington.getInstance().print("2");
-        Sington.getInstance().print("3");
-       Sington.getInstance().print("4");
-       
-    }
-}