DOC: Wrong output in the example of Timedelta.isoformat
#### Location of the documentation

[`pandas.Timedelta.isoformat`](https://pandas.pydata.org/docs/reference/api/pandas.Timedelta.isoformat.html#pandas.Timedelta.isoformat)

#### Documentation problem

The output on an example in the docs has the wrong output(`Timedelta.isoformat` works fine)

![Screenshot from 2020-12-04 16-40-36](https://user-images.githubusercontent.com/47276342/101234113-ce80fa00-36e2-11eb-8e2c-9623f41a69ae.png)

While it should've been `'P0DT1H0M10S'`
