GitLab

* [python-package] add type hints on Dataset constructors

* fix __init_from_list_np2d() hint

* add return type

* define a DatasetHandle type

[python-package] fix type hints on cptr converters

* [python-package] add type hints on Booster eval methods

* remove unnecessary changes

* fix hints

* [python-package] add more type hints in basic.py

* Booster handle is a c_void_p

[python-package] highlight the path a sample takes through a tree in `plot_tree` and `create_tree_digraph` (fixes #4784) (#5119)

* highlight path in plot_tree

* lint

* rename x to example_case. support categorical features. add test

* lint

* check for exactly one row. test empty example_case

* Apply suggestions from code review
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* handle missing values in numeric splits

* remove literal. add categorical split function

* make categorical feature more important. lint

* add enum. update categorical split. apply suggestions

* update numeric split decision

* lint

* Update python-package/lightgbm/plotting.py
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

MAINT Prefix NUMERIC_TYPES to make it a internal object