patch 9.1.0754: fixed order of items in insert-mode completion menu

Problem:  fixed order of items in insert-mode completion menu
Solution: Introduce the 'completeitemalign' option with default
          value "abbr,kind,menu" (glepnir).

Adding an new option `completeitemalign` abbr is `cia` to custom
the complete-item order in popupmenu.

closes: #14006
closes: #15760

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 49087d3..3980601 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -2102,6 +2102,16 @@
 	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.
 
+						*'completeitemalign'* *'cia'*
+'completeitemalign' 'cia' string (default: "abbr,kind,menu")
+			  global
+	A comma-separated list of |complete-items| that controls the alignment
+	and display order of items in the popup menu during Insert mode
+	completion. The supported values are abbr, kind, and menu. These
+	options allow to customize how the completion items are shown in the
+	popup menu.  Note: must always contain those three values in any
+	order.
+
 						*'completeopt'* *'cot'*
 'completeopt' 'cot'	string	(default: "menu,preview")
 			global or local to buffer |global-local|