Prefer (...) new argument forwarding syntax

[adityapandit17]

Prefer (...) over ruby2_keywords
(...) is already used in several places in Rails and looks nicer.

Reference :- eregon@191ee5e#comments

[casperisfine]

This is not equivalent. See the CI build failures.

[adityapandit17]

Thanks for pointing that out. I fixed that one.

[zzak]

Seems like there are failures in CI:

/rails/activesupport/lib/active_support/current_attributes.rb:165:in `method_missing'
--
  | /rails/activesupport/test/current_attributes_test.rb:164:in `block in <class:CurrentAttributesTest>'

[eugeneius]

Thank you for the pull request, but this is a cosmetic change, which we don't accept.

Note that 191ee5e was part of #42289, which fixed a bug.