patch 9.2.0423: popup: wrapped cmdline truncated with wildoptions=pum

patch 9.2.0423: popup: wrapped cmdline truncated with wildoptions=pum

Problem:  popup: wrapped cmdline truncated with wildoptions=pum
Solution: Call msg_starthere() in redrawcmd() to reset lines_left
          before each redraw (Yasuhiro Matsumoto).

redrawcmd() leaves lines_left at its previous value, which decrements
across successive redraws (e.g. when wildtrigger() refreshes the popup
on every keystroke) until 0, after which msg_no_more aborts drawing
the wrapped cmdline. Call msg_starthere() to reset it.

related: #20081

Signed-off-by: Yasuhiro Matsumoto <mattn.jp@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>