The documentation on `docker export` doesn't mention that data in volumes is not included in the export. This adds a note that volumes are not part of the export and refers to the "Backup, restore, or migrate data volumes" to give the user some pointers. Relates to https://github.com/docker/docker/issues/10095 Signed-off-by: Sebastiaan van Stijn <github@gone.nl> Upstream-commit: 67588d0ec4d73a8f2efb150d555c38b7ebfca7f6 Component: engine