[Translation] Doctrine translatable extension & behaviour are not for translating message *catalogues*

[jontjs]

Currently the docs mention the Doctrine translatable extension & behaviour in the Translation Resource/File Names and Locations section, but there are actually about translatable entities, not a way of storing message catalogues in a database.

Should they have their own section (called Translatable Entities?). If so, it should be before the Translatable Objects section because otherwise lazy readers will stop reading at Translatable Objects (because entities are objects, after all).

Or do they actually belong in the Translatable Objects section? I think they don't, but I don't know the TranslatableMessage feature well enough to be sure of that.