message: Fix LTR/RTL handling in Language::FromLanguageTag
  FromLanguageTag() didn't correctly set m_direction value.
  Observable effect was that text alignment was incorrect for XLIFF files
  (which use this function), but not for PO files (which use TryParse).
  Fixes
diff: @@ -406,6 +406,8 @@ Language Language::FromLanguageTag(const std::string& tag)
  if (std::regex_search(locale, m, re_private_subtag))
  lang.m_code += "@" + m.str(1);
  + lang.m_direction = DoIsRTL(lang) ? TextDirection::RTL : TextDirection::LTR;
  +
  return lang;
  }
  