[DOC] Fix docstrings for doc sprint #884
Description
Describe the issue linked to the documentation
Easy files to fix
- https://github.com/alan-turing-institute/sktime/blob/77c2547b7f05e2975962eca749d4c9f4f2b8468e/sktime/utils/_maint/_show_versions.py
- https://github.com/alan-turing-institute/sktime/blob/main/sktime/transformations/series/boxcox.py
- https://github.com/alan-turing-institute/sktime/blob/main/sktime/transformations/series/acf.py