Change number of flags

Author: vasilevx

9-regular-expressions/01-regexp-introduction/article.md

@@ -77,7 +77,7 @@ alert( "<h1> <h2> <h3>".search(regexp));
 
 Regular expressions may have flags that affect the search.
 
-There are only 5 of them in JavaScript:
+There are only 6 of them in JavaScript:
 
 `i`
 : With this flag the search is case-insensitive: no difference between `A` and `a` (see the example below).