message: XLIFF: Take language information from first <file>
  Previously it was repeatedly extracted from all of them, effectively
  using the last one, but more expensively.
diff: @@ -599,10 +599,20 @@ public:
  void XLIFF1Catalog::Parse(pugi::xml_node root)
  {
  int id = 0;
  + bool extractedLanguage = false;
  +
  for (auto file: root.children("file"))
  + {
  + // In XLIFF, embedded sub-files may have different languages, although it is
  + // unclear how common this is practice. Poedit doesn't support this yet, so
  + // take the first file's language only.
  + if (!extractedLanguage)
  {
  m_sourceLanguage = Language::TryParse(file.attribute("source-language").value());
  m_language = Language::TryParse(file.attribute("target-language").value());
  + extractedLanguage = true;
  + }
  +
  for (auto unit: file.select_nodes(".//trans-unit"))
  {
  auto node = unit.node();
  