patch 8.0.1373: no error when settting 'renderoptions' before starting GUI

Problem:    No error when settting 'renderoptions' to an invalid value before
            starting the GUI.
Solution:   Always check the value. (Ken Takata, closes #2413)
diff --git a/src/version.c b/src/version.c
index 3e84229..837ca02 100644
--- a/src/version.c
+++ b/src/version.c
@@ -772,6 +772,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1373,
+/**/
     1372,
 /**/
     1371,