add: ModifyGuildWelcomeScreen type

src/types/guilds/modify_guild_welcome_screen.ts

@@ -0,0 +1,16 @@
+import { SnakeCasedPropertiesDeep } from "../util.ts";
+import { WelcomeScreenChannel } from "./welcome_screen_channel.ts";
+
+export interface ModifyGuildWelcomeScreen {
+  /** Whether the welcome screen is enabled */
+  enabled?: boolean | null;
+  /** Channels linked in the welcome screen and their display options */
+  welcomeScreen?: WelcomeScreenChannel[] | null;
+  /** The server description to show in the welcome screen */
+  description?: string | null;
+}
+
+// TODO: add documentation link
+export type DiscordModifyGuildWelcomeScreen = SnakeCasedPropertiesDeep<
+  ModifyGuildWelcomeScreen
+>;