patch 9.0.2018: complete_info() returns wrong index

patch 9.0.2018: complete_info() returns wrong index

Problem:  complete_info() returns wrong index
Solution: Make order of 'info' in completion_info consistent

Start the iteration from the same point and follow the same direction as
done when assigning the completion numbers. This way we remove the
dependence on the completion direction and make the order of 'info'
consistent.

closes: #12230
closes: #12971

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: LemonBoy <thatlemon@gmail.com>