Returns all available target languages that are supported by this service when given a source language.
TranslatorInterface $translator: The translator entity.
$source_language: The source language.
array An array of remote languages in ISO format.
Overrides TranslatorPluginInterface::getSupportedTargetLanguages
public function getSupportedTargetLanguages(TranslatorInterface $translator, $source_language) {
$languages = tmgmt_available_languages();
return array_combine(array_keys($languages), array_keys($languages));
}