Fix example code in Active Job guide [ci skip]
Merge pull request #16659 from y-yagi/patch-4

Fix example code in Active Job guide [ci skip]
Don't trim excess whitespace in pg #columns_for_distinct

Fixes #16623 introduced by https://github.com/rails/rails/commit/3d5a2019bcccc6fb01bee4811ca669f4383edb51