Better transformation guide

documentation/docs/guides/transformation.mdx

@@ -42,7 +42,7 @@ In the example above, we have a `User` struct with two fields: `FirstName` and `
 When using the following controller, the data will be transformed before it is unmarshaled into the `User` struct.
 
 ```go
-func myController(c fuego.ContextWithBody[User]) (User, error) {
+func echoCapitalized(c fuego.ContextWithBody[User]) (User, error) {
 	user, err := c.Body()
 	if err != nil {
 		return User{}, err
@@ -53,3 +53,40 @@ func myController(c fuego.ContextWithBody[User]) (User, error) {
 	return u, nil
 }
 ```
+
+## Recursion
+
+Transformation is not recursive. If you have nested structs, you will need to transform each struct individually. This is done on purpose to give you more control over the transformation process.
+
+```go
+type Address struct {
+	Street string `json:"street"`
+	City   string `json:"city"`
+}
+
+func (a *Address) InTransform(ctx context.Context) error {
+	a.Street = strings.TrimSpace(a.Street)
+	a.City = strings.ToUpper(a.City)
+	return nil
+}
+
+type User struct {
+	FirstName string `json:"first_name"`
+	LastName  string `json:"last_name"`
+	// highlight-next-line
+	Address   Address `json:"address"` // Nested struct
+}
+
+func (u *User) InTransform(ctx context.Context) error {
+	u.FirstName = strings.ToUpper(u.FirstName)
+	u.LastName = strings.TrimSpace(u.LastName)
+
+// highlight-next-line
+	err := u.Address.InTransform(ctx) // Transform the nested struct
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+```

documentation/src/components/FlowChart.js

@@ -32,6 +32,7 @@ subgraph fuego
  click ErrorHandler "/fuego/docs/guides/errors" "Error Handling"
 end
 
+ErrorHandler -- JSON{b:'Error!'} --> resp(Response)
 Serialization -- JSON{b:'My Response!'} --> resp(Response)
 Controller -. JSON{b:'Custom Response!'} .-> resp(Response)