faq: add list element unpack to string ways

Signed-off-by: peefy <xpf6677@163.com>

Author: Peefy

docs/user_docs/support/faq-kcl.md

@@ -2339,3 +2339,16 @@ t_float: float = float(t_str)  # you will get "t_float: 1.0"
 ```
 
 For more information about type conversion, see [KCL Builtin Types](https://kcl-lang.io/docs/reference/lang/tour#built-in-types) and [KCL Type System](https://kcl-lang.io/docs/reference/lang/tour#type-system).
+
+## 51. Is there an easy way to unpack a list into a string?
+
+The KCL list provides built-in string formatting methods, which can be achieved using the str function or the format function of the str variable, such as the following code:
+
+```python
+allowed = ["development", "staging", "production"]
+
+schema Data:
+    environment: str
+    check:
+        environment in allowed, "environment must be one of {}".format(allowed)
+```

i18n/zh-CN/docusaurus-plugin-content-docs/current/user_docs/support/faq-kcl.md

@@ -2353,3 +2353,16 @@ t_float: float = float(t_str)  # 输出的 t_float 为一个浮点型 "t_float:
 ```
 
 如果您想查看更多详细的关于KCL类型系统和类型转换的内容，您可以查阅 [KCL 内置类型](https://kcl-lang.io/docs/reference/lang/tour#built-in-types) 和 [KCL 类型系统](https://kcl-lang.io/docs/reference/lang/tour#type-system)。
+
+## 51. 如何将列表类型的变量逐个解包到字符串中
+
+KCL 的列表提供了内置的字符串格式化方法，我们可以使用 str 函数或者 str 变量的 format 函数完成此类功能，比如下面的代码
+
+```python
+allowed = ["development", "staging", "production"]
+
+schema Data:
+    environment: str
+    check:
+        environment in allowed, "environment must be one of {}".format(allowed)
+```

i18n/zh-CN/docusaurus-plugin-content-docs/version-0.7.0/user_docs/support/faq-kcl.md

@@ -2353,3 +2353,16 @@ t_float: float = float(t_str)  # 输出的 t_float 为一个浮点型 "t_float:
 ```
 
 如果您想查看更多详细的关于KCL类型系统和类型转换的内容，您可以查阅 [KCL 内置类型](https://kcl-lang.io/docs/reference/lang/tour#built-in-types) 和 [KCL 类型系统](https://kcl-lang.io/docs/reference/lang/tour#type-system)。
+
+## 51. 如何将列表类型的变量逐个解包到字符串中
+
+KCL 的列表提供了内置的字符串格式化方法，我们可以使用 str 函数或者 str 变量的 format 函数完成此类功能，比如下面的代码
+
+```python
+allowed = ["development", "staging", "production"]
+
+schema Data:
+    environment: str
+    check:
+        environment in allowed, "environment must be one of {}".format(allowed)
+```

versioned_docs/version-0.7.0/user_docs/support/faq-kcl.md

@@ -2339,3 +2339,16 @@ t_float: float = float(t_str)  # you will get "t_float: 1.0"
 ```
 
 For more information about type conversion, see [KCL Builtin Types](https://kcl-lang.io/docs/reference/lang/tour#built-in-types) and [KCL Type System](https://kcl-lang.io/docs/reference/lang/tour#type-system).
+
+## 51. Is there an easy way to unpack a list into a string?
+
+The KCL list provides built-in string formatting methods, which can be achieved using the str function or the format function of the str variable, such as the following code:
+
+```python
+allowed = ["development", "staging", "production"]
+
+schema Data:
+    environment: str
+    check:
+        environment in allowed, "environment must be one of {}".format(allowed)
+```