Bug 34644: Add clarifying text to sysprefs to indicate that MarcFieldsToOrder is...

Bug 34644: Add clarifying text to sysprefs to indicate that MarcFieldsToOrder is a fallback to MarcItemFieldsToOrder

Clarify that fields will fall back to MarcFieldsToOrder from MarcItemFieldsToOrder.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 884039bd5af43ffc83aaf1ef93500c6ab56efc2a)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>