Bug fix: HTML minifier error in home page

[kimsauce]

Purpose of this pull request

Made Typography a "div" component to stop MUI from wrapping the header section in an invisible <p> tag. Eliminates this yarn build error:

[WARNING] Docusaurus static site generation process emitted warnings for 1 paths
This is non-critical and can be disabled with DOCUSAURUS_IGNORE_SSG_WARNINGS=true
Troubleshooting guide: https://github.com/facebook/docusaurus/discussions/10580

- "/":
  - [HTML minifier diagnostic - error] No "p" element in scope but a "p" end tag seen - {"primary_spans":[{"end":24161,"start":24157}],"span_labels":[]}

Select the type of change

• Minor Changes - Typos, formatting, slight revisions
• Update Content - Revisions, updating sections
• New Content - New features, sections, pages, tutorials
• Site and Tools - .clabot, version updates, maintenance, dependencies, new packages for the site (Docusaurus, Gatsby, React, etc.)

Ticket (if applicable)