patch 9.2.0713: completion: ruler not updated correctly when the popup menu is visible

patch 9.2.0713: completion: ruler not updated correctly when the popup menu is visible

Problem:  While the insert-mode completion popup menu is visible, the
          ruler - and the ruler shown in a status line when 'laststatus'
          is set - shows the column where the completion started instead
          of the real cursor column. With a status line the ruler can
          also stay at the column from before the completion until the
          next key is pressed.
Solution: Position the popup menu at the completion start column without
          moving the cursor there, so the ruler keeps reflecting the
          real cursor column.  Also mark the status line for redraw
          before the menu is shown, so its ruler is updated for the real
          cursor column while the menu is visible.

closes: #20626

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>