updated for version 7.4a.047

Problem:    Some comments are not so nice.
Solution:   Change the comments.

src/option.c

@@ -11452,6 +11452,7 @@ change_compatible(on)
 
 /*
  * Return TRUE when option "name" has been set.
+ * Only works correctly for global options.
  */
     int
 option_was_set(name)