Add documentation for the new interface

LineSDK/LineSDK/Login/LoginResult.swift

@@ -23,10 +23,14 @@ import Foundation
 
 /// Represents a successful login.
 public struct LoginResult {
-
+
+    /// Represents a login route for how the auth flow is initiated.
     public enum LoginRoute: String {
+        /// The auth flow starts with a LINE app universal link.
         case appUniversalLink
+        /// The auth flow starts with a LINE customize URL scheme.
         case appAuthScheme
+        /// The auth flow starts in a web page inside LINE SDK.
         case webLogin
     }
 
@@ -45,7 +49,12 @@ public struct LoginResult {
     /// The `nonce` value when requesting ID Token during login process. Use this value as a parameter when you
     /// verify the ID Token against the LINE server. This value is `nil` if `.openID` permission is not requested.
     public let IDTokenNonce: String?
-
+    /// Describes how the authentication flow was initiated for this login result.
+    ///
+    /// If the LINE app was launched to obtain this result, the value will be either `.appUniversalLink` or
+    /// `.appAuthScheme`, depending on how the LINE app was opened. If authentication occurred via a web page within
+    /// the LINE SDK, the value will be `.webLogin`. If the authentication flow was never initiated, the value will
+    /// be `nil`.
     public let loginRoute: LoginRoute?
 }