Edit error messages.
Edit error messages.

Asked Michael about the error messages we're using and he got
back to me with some newer ones.
He says they're "[s]lightly more concise and direct."

alphagov/digitalmarketplace-supplier-frontend,mtekel/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend,mtekel/digitalmarketplace-supplier-frontend,mtekel/digitalmarketplace-supplier-frontend,mtekel/digitalmarketplace-supplier-frontend,alphagov/digitalmarketplace-supplier-frontend