cleanup, remove trailing whitespace from guides/CHANGELOG
Removed deprecated threadsafe!
Merge pull request #11279 from jetthoughts/removed_threadsafe_deprectaed_option

Removed deprecated threadsafe! from Rails Config
Added missing CHANGELOG from PR #11279 [ci skip]
Merge pull request #11280 from arunagw/added-missing-changelog-entry

Added missing CHANGELOG from PR #11279 [ci skip]
Removed unused deprecation requires.
Merge pull request #11281 from jetthoughts/remove_unused_deprecation_requires

Removed unused deprecation requires.
removed deprecated increment_open_transactions
Remove deprecated `decrement_open_transactions`.
Remove deprecated `transaction_joinable=`

in favor of `begin_transaction`
with `:joinable` option.
Remove deprecated `scope` use without passing a callable object.

Removed tests from deprecated code.