patch 8.2.4204: screenpos() has non-zero row for invisible text

Problem:    screenpos() has non-zero row for invisible text.
Solution:   Only add the window row when the text is visible. (closes #9618)
diff --git a/src/version.c b/src/version.c
index c75fe99..2208c1c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4204,
+/**/
     4203,
 /**/
     4202,