EMPTY_BACKTRACE is not defined

[greenfork]

Dry::Logger::Formatters::String#format_exception method references the EMPTY_BACKTRACE constant but it is never defined.

dry-logger/lib/dry/logger/formatters/string.rb

Lines 95 to 102 in 34039a1

	# @since 1.0.0
	# @api private
	def format_exception(value)
	[
	"#{value.message} (#{value.class})",
	format_backtrace(value.backtrace || EMPTY_BACKTRACE)
	].join(NEW_LINE)
	end