fix typo 'report' -> 'refer' (#115)

Author: PilkeySEK

docs/tutorials/programming-language/main/02-00-basics/02-04-data-types.md

@@ -150,7 +150,7 @@ string contains another, e.g.
 if ("ere" in "Able was I ere I saw Elba.") //...
 ```
 
-For more information, please report to 
+For more information, please refer to 
 [the complete overview of the string class](http://www.valadoc.org/glib-2.0/string.html).
 
 A [sample program](../../../../developer-guides/string-sample) demonstrating string usage is also available.