GitLab

* promote objective and init_score to top-level arguments

* follow comments

* Update R-package/R/lightgbm.R
Co-authored-by: James Lamb <jaylamb20@gmail.com>

* update docs

* linter

* comments

* comments

* comments

* extend test for default objective

* Update R-package/tests/testthat/test_basic.R
Co-authored-by: James Lamb <jaylamb20@gmail.com>