feat: add {add,remove}GroupDMRecipient methods (#11135)

* feat: add `{add,delete}GroupDMRecipient methods`

* fix: requested changes

---------

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/core/scripts/check-routes.mjs

@@ -0,0 +1,34 @@
+import { Routes } from 'discord-api-types/v10';
+import { glob, readFile } from 'node:fs/promises';
+
+const usedRoutes = new Set();
+
+const ignoredRoutes = new Set([
+	// Deprecated
+	'channelPins',
+	'channelPin',
+	'guilds',
+	'guildCurrentMemberNickname',
+	'guildMFA',
+	'nitroStickerPacks',
+]);
+
+for await (const file of glob('src/api/*.ts')) {
+	const content = await readFile(file, 'utf-8');
+
+	const routes = content.matchAll(/Routes\.([\w\d_]+)/g);
+	for (const route of routes) {
+		usedRoutes.add(route[1]);
+	}
+}
+
+const unusedRoutes = Object.keys(Routes).filter((route) => !usedRoutes.has(route) && !ignoredRoutes.has(route));
+
+if (unusedRoutes.length > 0) {
+	console.warn('The following routes are not implemented:');
+	for (const route of unusedRoutes) {
+		console.warn(` - ${route}`);
+	}
+} else {
+	console.log('No missing routes.');
+}