The syntax of a document translation is ignored, and the syntax of the default language is used instead

This affects both the content rendering, and the choice of the WYSIWYG editor.

To reproduce:

• make the wiki multilingual (use en and fr as possible languages)
• create a document in the English language with the 2.0 syntax, use = 2.0 title = as the content
• create a French translation, switch the language to 1.0, leave the same content
• view the translated document: the 2.0 title is incorrectly rendered in the 1.0 document
• edit (WYSIWYG) the translation: the GWT editor is used instead of the TinyMCE one