Minor issues with documentation of `TimeSeries`

- [ ] Most methods are missing examples.
- [ ] For the ones that do, the examples are overindented, so no syntax highlighting is applied (example: [`TimeSeries.plot_lagplot`](https://library.safeds.com/en/latest/reference/safeds/data/tabular/containers/TimeSeries/#safeds.data.tabular.containers.TimeSeries.plot_lagplot)).