docs(discussions): add a list example

examples/discussions/list.ts

@@ -0,0 +1,24 @@
+import { authenticatePronoteCredentials, PronoteApiAccountId } from "../../src";
+
+(async () => {
+  const pronote = await authenticatePronoteCredentials("https://pronote-vm.dev/pronote", {
+    accountTypeID: PronoteApiAccountId.Student,
+    username: "lisa.boulanger", // using my VM credentials here because the demo instance doesn't have any messages.
+    password: "12345678",
+
+    // Because this is just an example, don't forget to change this.
+    deviceUUID: "my-device-uuid"
+  });
+
+  // Get an overview of available discussions.
+  const discussionsOverview = await pronote.getDiscussionsOverview();
+  // Select the first discussion available.
+  const firstDiscussion = discussionsOverview.discussions[0];
+
+  // Fetch the messages overview from the discussion.
+  // You need to fetch the overview in order to send a message.
+  const messagesOverview = await firstDiscussion.fetchMessagesOverview();
+  console.info(firstDiscussion.subject);
+  console.log("Currently containing", messagesOverview.messages.length, "message(s)...");
+})();
+