1) Wrap step param into double `` in the AutoRegressivePipeline docs.
2) Fix problem with linting.
3) Add a link to the pull request in the CHANGELOG.md

1) Add space between "Autocorrelation function" and (ACF, pho(t)) and the same for PACF.
2) Add a link to the pull request in the CHANGELOG.md

…ble` docs

* Fix links in 'See Also' references in `Pipeline` docs
* Fix links in 'See Also' references in `AutoRegressivePipeline` docs
* Fix links in 'See Also' references in `DirectEnsemble` docs

* Add external links to `CatBoostRegressor` in `CatBoostMultiSegmentModel` and
  `CatBoostPerSegment` docs.

* Add external links to `LinearRegression` in `LinearMultiSegmentModel`
  and `LinearPerSegmentModel` docs.

* Add external links to `ElasticNet` in `ElasticMultiSegmentModel` and
  `ElasticPerSegmentModel` docs.