refactor(helpers): separate functions into files (#667)

* refactor(helpers): separate functions into files

* idk

* idk

src/helpers/messages/unpin_message.ts

@@ -0,0 +1,17 @@
+import { RequestManager } from "../../rest/request_manager.ts";
+import { endpoints } from "../../util/constants.ts";
+import { requireBotChannelPermissions } from "../../util/permissions.ts";
+
+/** Unpin a message in a channel. Requires MANAGE_MESSAGES. */
+export async function unpin(channelID: string, messageID: string) {
+  await requireBotChannelPermissions(channelID, ["MANAGE_MESSAGES"]);
+
+  const result = await RequestManager.delete(
+    endpoints.CHANNEL_PIN(channelID, messageID),
+  );
+
+  return result;
+}
+
+// aliases
+export { unpin as unpinMessage };