Fix a typo in 1.6.6 (function object, NFE)

1-js/06-advanced-functions/06-function-object/article.md

@@ -347,7 +347,7 @@ If the function is declared as a Function Expression (not in the main code flow)
 
 Also, functions may carry additional properties. Many well-known JavaScript libraries make great use of this feature.
 
-They create a "main" function and attach many other "helper" functions to it. For instance, the [jQuery](https://jquery.com) library creates a function named `$`. The [lodash](https://lodash.com) library creates a function `_`, and then adds `_.clone`, `_.keyBy` and other properties to it (see the [docs](https://lodash.com/docs) when you want learn more about them). Actually, they do it to lessen their pollution of the global space, so that a single library gives only one global variable. That reduces the possibility of naming conflicts.
+They create a "main" function and attach many other "helper" functions to it. For instance, the [jQuery](https://jquery.com) library creates a function named `$`. The [lodash](https://lodash.com) library creates a function `_`, and then adds `_.clone`, `_.keyBy` and other properties to it (see the [docs](https://lodash.com/docs) when you want to learn more about them). Actually, they do it to lessen their pollution of the global space, so that a single library gives only one global variable. That reduces the possibility of naming conflicts.
 
 
 So, a function can do a useful job by itself and also carry a bunch of other functionality in properties.