Update externs for closure compiler to prevent renaming of transformRequest property.

i would like to be able to have following code working when using Closure JS compiler:

my.module.config(['$httpProvider', function($httpProvider) {
  $httpProvider.defaults.transformResponse = [my.transformHttpResponse];
}]);

unfortunately "transformResponse" is being renamed to random string.

Looks like Closure compiler doesn't respect @tyedef, i could inline all properties of angular.$http.Config but first wanted to get a quick feedback if that change makes sense.