Fixed the `repeat` attribute in a set of samples

Without seeing the data model I'm not 100% sure that the current `repeat="{{items}}"` is incorrect, but I get a feeling from reading the rest of the docs that these examples should read `repeat="{{item in items}}"`.

It would imply a cleaner data model, at least.
Merge pull request #437 from jeffposnick/patch-4

Fixed the repeat attribute in a set of samples