patch 8.1.0658: deleting signs and completion for :sign is insufficient

Problem:    Deleting signs and completion for :sign is insufficient.
Solution:   Add deleting signs in a specified or any group from the current
            cursor location.  Add group and priority to sign command
            completion. Add tests for different sign unplace commands. Update
            help text.  Add tests for sign jump with group. Update help for
            sign jump. (Yegappan Lakshmanan, closes #3731)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index d94bf8d..13e6d6e 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -11600,12 +11600,12 @@
     {
 	// Delete the sign in all the buffers
 	FOR_ALL_BUFFERS(buf)
-	    if (sign_unplace(sign_id, group, buf) == OK)
+	    if (sign_unplace(sign_id, group, buf, 0) == OK)
 		rettv->vval.v_number = 0;
     }
     else
     {
-	if (sign_unplace(sign_id, group, buf) == OK)
+	if (sign_unplace(sign_id, group, buf, 0) == OK)
 	    rettv->vval.v_number = 0;
     }
     vim_free(group);