💻 Indicate untranslated content to users

[boryanagoncharenko]

In #5187 we stopped copying the English content to all other languages. With this issue we should display to the users which parts of the content are not yet translated and give them an easy way to translate this content. This is the original text of #5187 from Felienne: It is not always clear to teachers untranslated content is shown when they see English content, it would be nice if we can show an icon or something (or a different color) if a content block is not translated.

[AnneliesVlaar]

A temporarily option could be to redirect people to the translation wiki within the feedback window when clicking on the feedback button. Maybe like this: