chore: Make display headings use the correct class
This following on from gitlab-org/gitlab-ui!3938 (merged), this MR updates gl-heading-0
to use gl-heading-display
- /pages/components/overview.vue
- /pages/_section/_slug.vue
This following on from gitlab-org/gitlab-ui!3938 (merged), this MR updates gl-heading-0
to use gl-heading-display