Feature: Annotate auto-translated values

[mltsy]

When running i18n-tasks translate-missing it would be great if there were an option to annotate the resulting values with a comment like # translated by google so that the user can later search for and refine those when they have the resources.

It's almost possible to do this with awk (translate-missing -f yaml | awk '{print $0" # translated by google"}'), but with the yaml keys for hash values on their own line and multi-line values, etc. it gets... well... awkward 😉