fix(guide): add more headings

apps/guide/src/components/Mdx.tsx

@@ -3,6 +3,9 @@
 import { Alert, Section, DiscordMessages, DiscordMessage, DiscordMessageEmbed } from '@discordjs/ui';
 import { useMDXComponent } from 'next-contentlayer/hooks';
 import H1 from './H1';
+import H2 from './H2';
+import H3 from './H3';
+import H4 from './H4';
 import { DocsLink } from '~/components/DocsLink';
 import { ResultingCode } from '~/components/ResultingCode';
 
@@ -20,6 +23,9 @@ export function Mdx({ code }: { code: string }) {
 				DocsLink,
 				ResultingCode,
 				h1: H1,
+				h2: H2,
+				h3: H3,
+				h4: H4,
 			}}
 		/>
 	);