chore: use markdown headings instead of storybook blocks

Author: rubencarvalho

second-gen/packages/swc/.storybook/guides/code_of_conduct.mdx

@@ -1,9 +1,4 @@
-import { Meta, Title } from '@storybook/blocks';
-
-<Meta title="Adobe Code of Conduct" />
-
-<Title>Adobe Code of Conduct</Title>
-<br />
+# Adobe Code of Conduct
 
 ## Our Pledge
 

second-gen/packages/swc/.storybook/guides/s2_migration.mdx

@@ -1,7 +1,4 @@
-import { Meta, Title } from '@storybook/blocks';
-
-<Meta title="Migration guide" />
-<Title>Migration guide</Title>
+# Migration guide
 
 When migrating a component from the 1st generation to the 2nd generation, there are a few things to keep in mind.