patch 9.0.0118: no test for what patch 9.0.0155 fixes

Problem:    No test for what patch 9.0.0155 fixes.
Solution:   Add a test. Fix typos.  (closes #10822)
diff --git a/src/globals.h b/src/globals.h
index 86472ac..1fadc74 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1729,5 +1729,5 @@
 // overrules p_magic.  Otherwise set to OPTION_MAGIC_NOT_SET.
 EXTERN optmagic_T magic_overruled INIT(= OPTION_MAGIC_NOT_SET);
 
-// Set when 'cmdheight' is changed from non-zero to one temporarily.
+// Set when 'cmdheight' is changed from zero to one temporarily.
 EXTERN int made_cmdheight_nonzero INIT(= FALSE);