Merge branch 'docs-style-headings-example-fix' into 'master'

Fix headings example to only show sample headings

See merge request gitlab-org/gitlab!38357

doc/development/documentation/styleguide.md

@@ -265,8 +265,8 @@ because it’s friendly and easy to understand.
 
 Use sentence case. For example:
 
-- `## Use variables to configure pipelines`
-- `You can use the To-Do List.`
+- `# Use variables to configure pipelines`
+- `## Use the To-Do List`
 
 #### UI text