feat: 优化print函数，简化参数输出逻辑

src/interpreter/builtins/io.rs

@@ -3,10 +3,7 @@
 use crate::interpreter::Value;
 
 pub fn print(args: Vec<Value>) -> Value {
-    for (i, arg) in args.iter().enumerate() {
-        if i > 0 {
-            print!(" ");
-        }
+    for arg in args.iter() {
         print!("{}", arg);
     }
     println!();