Address heading structure on icon list page

[sarah-sch]

Statement of problem

On the icons list component page, example text under "Rich Content" and "Custom Size Rich Content" are marked as headings. The example content headings make the overall page structure, including in-page navigation, confusing. However, we also need to consider whether this particular component requires headings to be used as part of the code.

Work to be done

• [ ] Discuss problem with dev and accessibility team to align on solution
• [ ] Execute solution or create a new issue for solution