lib/asciidoctor/iso/deprecated.rb
warn "Please replace your references to Asciidoctor::ISO with Metanorma::ISO "\
"and your instances of require 'asciidoctor/iso' with "\
"require 'metanorma/iso'"
exit 127 if ENV["METANORMA_DEPRECATION_FAIL"]
Asciidoctor::ISO = Metanorma::ISO unless defined? Asciidoctor::ISO