patch 8.2.4532: suspending with CTRL-Z does not work on OpenBSD

Problem:    Suspending with CTRL-Z does not work on OpenBSD.
Solution:   Adjust #ifdef for SIGTSTP. (Stuart Henderson, closes #9912)
diff --git a/src/version.c b/src/version.c
index 9b25ef0..9248ca4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4532,
+/**/
     4531,
 /**/
     4530,