Enable Style/RedundantDoubleSplatHashBraces rubocop cop

[fatkodima]

While working through #49576, I identified some code in the relevant class, which can be improved via rubocop.

rails/activesupport/lib/active_support/number_helper/number_converter.rb

Lines 166 to 172 in 8ab5e58

	def translate_number_value_with_default(key, **i18n_options)
	I18n.translate(key, **{ default: default_value(key), scope: :number }.merge!(i18n_options))
	end
	def translate_in_locale(key, **i18n_options)
	translate_number_value_with_default(key, **{ locale: options[:locale] }.merge(i18n_options))
	end

Also fixed 2 new offenses for Style/RedundantReturn in the md files along the way.

I also updated rubocop to include the changes I suggested to rubocop after this finding - rubocop/rubocop#12257