patch 9.0.0519: the win_line() function is much too long

Problem:    The win_line() function is much too long.
Solution:   Move the code to draw the line number to a separate function.
diff --git a/src/version.c b/src/version.c
index 05dc50c..bc90293 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    519,
+/**/
     518,
 /**/
     517,