patch 9.1.1389: completion: still some issue when 'isexpand' contains a space

Problem:  Cannot get completion startcol when space is not the first
          trigger character (after v9.1.1383)
Solution: Detect the next comma followed by a space in the option string
          and use in next compare loop (glepnir)

closes: #17311

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1389,
 /**/
     1388,
 /**/