docs: optimize hertz vd tag description (#995)

Co-authored-by: kinggo <lilong.21@bytedance.com>

content/en/docs/hertz/tutorials/basic-feature/binding-and-validate.md

@@ -74,7 +74,30 @@ If [api-annotations](/docs/hertz/tutorials/toolkit/annotation/#supported-api-ann
 | json     | This tag is used to bind json parameters in the request body which content-type is `application/json`                                                                                                                                                                                                                   |
 | raw_body | This tag is used to bind the original body (bytes type) of the request, and parameters can be bound even if the bound field name is not specified. (Note: raw_body has the lowest binding priority. When multiple tags are specified, once other tags successfully bind parameters, the body content will not be bound) |
 | vd       | `vd` short for validator, [The grammar of validation parameter](https://github.com/bytedance/go-tagexpr/tree/master/validator)                                                                                                                                                                                          |
-| default  | Set default value                                                                                                                                                                                                                                                                                                       |
+| default  | Set default value |
+
+### Parameter Validation
+
+Specific validation syntax can be referred to [The grammar of validation parameter](https://github.com/bytedance/go-tagexpr/tree/master/validator).
+
+When generating code without IDL, directly tag the corresponding structure field, for example:
+
+```go
+type InfoRequest struct {
+		Name         string   `vd:"$!='your string'"`
+}
+```
+
+When generating code through IDL, corresponding annotations need to be added, please refer to [field-annotation](/docs/hertz/tutorials/toolkit/annotation/#field-annotation).
+
+Here are common usage examples:
+
+- length validation for string and list `len($)>0`
+- regex pattern match for string `regexp('^\\w*$')"`
+- value validation for numertic field `$>0`
+- validation for pointer field `num==nil || num>0`
+- validation for enum types `type=="hello" || type == "world"`
+- custom error message `msg:'C must be false when S.A>0'"`
 
 ### Parameter binding precedence
 

content/zh/docs/hertz/tutorials/basic-feature/binding-and-validate.md

@@ -76,6 +76,29 @@ func main() {
 | vd       | 参数校验，[校验语法](https://github.com/bytedance/go-tagexpr/tree/master/validator)                                                                                                   |
 | default  | 设置默认值                                                                                                                                                                        |
 
+### 参数校验
+
+具体校验语法可参考[校验语法](https://github.com/bytedance/go-tagexpr/tree/master/validator)。
+
+不通过 IDL 生成代码时直接在对应结构体字段打 tag，示例：
+
+```go
+type InfoRequest struct {
+		Name         string   `vd:"$!='your string'"`
+}
+```
+
+通过 IDL 生成代码时需添加相应的注解，可参考[Field 注解](/zh/docs/hertz/tutorials/toolkit/annotation/#field-注解)。
+
+下面给出常见用法：
+
+- string 和 list 的长度验证 `len($)>0`
+- 字符串正则匹配 `regexp('^\\w*$')"`
+- 验证数字字段的的值 `$>0`
+- 验证指针字段 `num==nil || num>0`
+- 验证枚举类型 `type=="hello" || type == "world"`
+- 自定义错误信息 `msg:'C must be false when S.A>0'"`
+
 ### 参数绑定优先级
 
 ```text