We need to call trim() function

Author: soswow

chapters/strings/trimming-whitespace-from-a-string.md

@@ -39,7 +39,7 @@ Opera, Firefox and Chrome all have a native string prototype `trim` method, and
 {% highlight coffeescript %}
 unless String::trim then String::trim = -> @replace /^\s+|\s+$/g, ""
 
-"  padded string  ".trim
+"  padded string  ".trim()
 # => 'padded string'
 {% endhighlight %}