patch 8.1.0614: placing signs can be complicated

Problem:    Placing signs can be complicated.
Solution:   Add functions for defining and placing signs.  Introduce a group
            name to avoid different plugins using the same signs. (Yegappan
            Lakshmanan, closes #3652)
diff --git a/src/version.c b/src/version.c
index c6d55d8..d59c9a2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    614,
+/**/
     613,
 /**/
     612,