patch 9.0.1729: screenpos() wrong when w_skipcol and cpoptions+=n

Problem:    screenpos() wrong result with w_skipcol and cpoptions+=n
Solution:   Use adjust_plines_for_skipcol() instead of subtracting
            w_skipcol.

closes: #12625

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1729,
 /**/
     1728,
 /**/