patch 9.0.0458: splitting a line with a text prop "above" moves it down

Problem:    Splitting a line with a text prop "above" moves it to a new line
            below.
Solution:   Keep an "above" text prop above the first line.

src/version.c

@@ -703,6 +703,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    458,
 /**/
     457,
 /**/