fix

9-regular-expressions/02-regexp-character-classes/article.md

@@ -153,9 +153,9 @@ Luckily, there's an alternative, that works everywhere. We can use a regexp like
 alert( "A\nB".match(/A[\s\S]B/) ); // A\nB (match!)
 ```
 
-The pattern `pattern:[\s\S]` literally says: "a space character OR not a space character". In other words, "anything".
+The pattern `pattern:[\s\S]` literally says: "a space character OR not a space character". In other words, "anything". We could use another pair of complementary classes, such as `pattern:[\d\D]`, that doesn't matter.
 
-This works everywhere. Also we can use it if we don't want to use `pattern:s` flag, in cases when we want a regular "no-newline" dot too in the pattern.
+This trick works everywhere. Also we can use it if we don't want to use `pattern:s` flag, in cases when we want a regular "no-newline" dot too in the pattern.
 ````
 
 ````warn header="Pay attention to spaces"