Request update to 18F Content Guide to have all lowercase for 'Design System'

[brunerae]

The 18F Content Guide says that mentions of 'Design System' in reference to USWDS should use title case. At our January 31st CS/UX sync (GDrive 🔒), we decided to use all lowercase in these instances. We should ask 18F to update these guidelines so that there is consistency across government when talking about USWDS.

[annepetersen]

I might be able to help with this