FIX regexp

The regexp being used fails if the datatable is not initialised with empty data.

When the table is empty, we try to match an expression that looks like this :
`<!-- ngRepeat: v in a.b --><!-- end ngRepeat: v in a.b -->`

ngRepeatAttr is then correctly matched to `a.b`

When the table is NOT empty, then the expression looks more like this :
`<!-- ngRepeat: v in a.b --><tr ng-repeat="v in a.b" class="ng-scope">...`

ngRepeatAttr is then set to `a.b"` (with a quote at the end of the expression)

We should use a `.+?` as a non-greedy version of `.+` to match only the expression inside the comment