feat: for..in 范围语法 .. 改为 to 关键字

docs/language-reference.md

@@ -188,13 +188,13 @@ while i < 5 {
 ### for 循环
 
 ```rust
-for i in 0..5 {
+for i in 0 to 5 {
     print_i64(i);
 }
 // 输出: 0 1 2 3 4
 ```
 
-`for i in start..end` 等价于 `let mut i = start; while i < end { ...; i += 1; }`
+`for i in start to end` 等价于 `let mut i = start; while i < end { ...; i += 1; }`
 
 ### match
 
@@ -566,7 +566,7 @@ l_lang.exe source.l --emit-ir
 类型:    i64  f64  bool  str  void  struct  enum  [T;N]
 声明:    let x = val          let mut x = val
          let x: Type = val    type Alias = Type
-控制流:  if/else  while  for i in 0..N  match
+控制流:  if/else  while  for i in 0 to N  match
 函数:    fn name(p: T) -> Ret { return expr; }
 结构体:  struct Name { f: Type }   Name { f: val }
 枚举:    enum Name { A, B, C }     Name::B