docs: add type definition for ReminderManagementServiceClient (#501)

docs/en/Calling-Alexa-Service-APIs.rst

@@ -581,4 +581,23 @@ Type Definition
     getSystemDistanceUnits(deviceId: string): Promise<services.ups.DistanceUnits>;
     getSystemTemperatureUnit(deviceId: string): Promise<services.ups.TemperatureUnit>;
     getSystemTimeZone(deviceId: string): Promise<string>;
-  }
+  }
+
+ReminderManagementServiceClient
+===============================
+
+``ReminderManagementServiceClient`` can be used to query `Alexa Reminders API <https://developer.amazon.com/docs/smapi/alexa-reminders-api-reference.html>`_ to create and manage reminders from your skill.
+
+Type Definition
+---------------
+
+.. code-block:: typescript
+
+    class ReminderManagementServiceClient extends BaseServiceClient {
+      deleteReminder(alertToken: string): Promise<void>;
+      getReminder(alertToken: string): Promise<services.reminderManagement.GetReminderResponse>;
+      updateReminder(alertToken: string, reminderRequest: services.reminderManagement.ReminderRequest): Promise<services.reminderManagement.ReminderResponse>;
+      deleteReminders(): Promise<void>;
+      getReminders(): Promise<services.reminderManagement.GetRemindersResponse>;
+      createReminder(reminderRequest: services.reminderManagement.ReminderRequest): Promise<services.reminderManagement.ReminderResponse>;
+    }