Switch apt/reboot doc to the 'main' manual
Switch apt/reboot doc to the 'main' manual

Previously we directed people to a specific apt/security manual for the
alert, but we also maintain a generic 'reboot' manual that seems to
cover it. This replaces the specific manual with the generic one.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet