patch 8.2.1523: still not enough test coverage for the spell file handling

Problem:    Still not enough test coverage for the spell file handling.
Solution:   Add spell file tests. (Yegappan Lakshmanan, closes #6790)

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1523,
 /**/
     1522,
 /**/