patch 8.1.0567: error for NUL byte in ScreenLines goes unnoticed

Problem:    Error for NUL byte in ScreenLines goes unnoticed.
Solution:   Add an internal error message.

src/version.c

@@ -792,6 +792,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    567,
 /**/
     566,
 /**/