[Translation:update][Xliff Dumper] added target-language.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11218
| License       | MIT
@stof I'm in charge of the issue today. I don't understand what's wrong with the current implementation. What would you do ?