Steps to Reproduce:
Mark the documentation of a module for translation (this happened on MediaWiki.org with Module:Transcluder/doc).
Try to translate the page into another language.
When the page is marked for translation the "translation" into the source language (Module:Transcluder/doc/en) was not created.
When the page is translated into a new language, the translation page (Module:Transcluder/doc/<language code>) was not created
Translations of module documentation pages are automatically created in the same manner as translations of all other pages.