Update whitehall translation documentation to match correct process
Update whitehall translation documentation to match correct process

Content schema tests will intermittently fail if government-frontend and
whitehall have not been updated, because it may try to access the new
language before these have been added to the other apps.

alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs