Move typography settings to theme.json

Summary

We can move some of our typography settings to theme.json, which would simplify our code and be more in line with WordPress guidelines.

Tasks

• Move link colors to theme file
• Move heading font style and font family to theme file
• Write some documentation about theme.json in Gitbook

Resources

Full-site editing typography options:

• https://fullsiteediting.com/lessons/theme-json-typography-font-styles/
• https://fullsiteediting.com/lessons/theme-json-typography-options/
• https://fullsiteediting.com/lessons/global-styles/