fix

Author: iliakan

9-regular-expressions/13-regexp-alternation/02-find-matching-bbtags/solution.md

@@ -20,4 +20,4 @@ let str = `
 alert( str.match(regexp) ); // [b]hello![/b],[quote][url]http://google.com[/url][/quote]
 ```
 
-Please note that we had to escape a slash for the closing tag `pattern:[/\1]`, because normally the slash closes the pattern.
+Please note that besides escaping `pattern:[` and `pattern:]`, we had to escape a slash for the closing tag `pattern:[\/\1]`, because normally the slash closes the pattern.

9-regular-expressions/13-regexp-alternation/02-find-matching-bbtags/task.md

@@ -15,7 +15,7 @@ Normal:
 [url] [b]http://google.com[/b] [/url]
 [quote] [b]text[/b] [/quote]
 
-Impossible:
+Can't happen:
 [b][b]text[/b][/b]
 ```