ADD fullscreen layout to a few stories that need it

examples/official-storybook/stories/addon-docs/container-override.stories.mdx

@@ -14,4 +14,4 @@ import { Meta, DocsContainer } from '@storybook/addon-docs/blocks';
   }}
 />
 
-<Story name='dummy'><div>some content</div></Story>
+<Story name='dummy' parameters={{ layout: 'fullscreen' }}><div>some content</div></Story>

examples/official-storybook/stories/addon-docs/mdx.stories.js

@@ -5,6 +5,9 @@ import markdown from './markdown.stories.mdx';
 export default {
   title: 'Addons/Docs/mdx-in-story',
   decorators: [(storyFn) => <DocsContainer context={{}}>{storyFn()}</DocsContainer>],
+  parameters: {
+    layout: 'fullscreen',
+  },
 };
 
 // This renders the contents of the docs panel into story content