Clarify values used in the evaluation in the forecast example

In the evaluation method data from the second year is transformed by the model.
Previewing the predictions I see 7 values for ForecastedRentals in the results. I assumed that is because of the horizon = 7.


What do the values represent? Is that one week after the training data, i.e forecast starts at 2012-01-01?
Or is it forecasting after the second year has been added by transforming the testdata, i.e forecast starts at 2013-01-01?

In either case it looks like the example code only looks at the first day of each prediction (ForecastedRentals[0]).
Can that really be compared with actual values from the testdata, which has period 1 day rather than 7 days?

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* ID: 32d03435-cc6c-1123-a86c-d5c3eacc24bd
* Version Independent ID: 460afd2b-383d-7b90-6804-4b900c3bc9b2
* Content: [Tutorial: Forecast bike rental demand - time series - ML.NET](https://docs.microsoft.com/en-us/dotnet/machine-learning/tutorials/time-series-demand-forecasting)
* Content Source: [docs/machine-learning/tutorials/time-series-demand-forecasting.md](https://github.com/dotnet/docs/blob/main/docs/machine-learning/tutorials/time-series-demand-forecasting.md)
* Product: **dotnet-ml**
* GitHub Login: @luisquintanilla
* Microsoft Alias: **luquinta**