Problem: Keys valid in CTRL-X mode are never mapped while insert
completion is active, so <C-N> and <C-P> cannot be remapped
for completion started by complete().
Solution: Do not disable mappings in CTRL_X_EVAL mode. In this mode a
mapping cannot interfere with selecting the completion
method, which is what the no-mapping rule exists for.
related: vim/vim#6440
related: vim/vim#16880
closes: vim/vim#20489076585e6ad
Co-authored-by: Thomas M Kehrenberg <tmke8@posteo.net>
2e8c60cb38