patch 8.1.1570: icon signs not displayed properly in the number column

Problem:    Icon signs not displayed properly in the number column.
Solution:   Display them properly. (Yegappan Lakshmanan, closes #4559)
diff --git a/src/version.c b/src/version.c
index 7e97f91..d71b86e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1570,
+/**/
     1569,
 /**/
     1568,