Improve readability of contributing to rails guide. [ci skip]
Merge pull request #14843 from tgxworld/improve_readability_of_contributing_to_rails_guide

[ci skip] Improve readability of contributing to rails guide.
Fix a typo in the doc of forty_two AR FinderMethod
Merge pull request #14858 from ebouchut/patch-1

Fix a typo in the doc of forty_two AR FinderMethod [ci skip]