message: Use different config key for extractors list
  This is for compatibility with Poedit 1.8 so that it's possible to go
  back temporarily. Otherwise Poedit 2 would remove extractors when custom
  ones are modified.
diff: @@ -53,8 +53,12 @@ inline void DoReadLegacyExtractors(wxConfigBase *cfg, F&& action)
  {
  cfg->SetExpandEnvVars(false);
  + wxString list = cfg->Read("/Parsers/CustomExtractorsList", "");
  + if (list.empty())
  + list = cfg->Read("/Parsers/List", "");
  +
  wxString oldpath = cfg->GetPath();
  - wxStringTokenizer tkn(cfg->Read("/Parsers/List", wxEmptyString), ";");
  + wxStringTokenizer tkn(list, ";");
  while (tkn.HasMoreTokens())
  {
  @@ -98,7 +102,7 @@ void LegacyExtractorsDB::Write(wxConfigBase *cfg)
  for (i = 1; i < Data.size(); i++)
  list << ";" << Data[i].Name;
  }
  - cfg->Write("/Parsers/List", list);
  + cfg->Write("/Parsers/CustomExtractorsList", list);
  wxString oldpath = cfg->GetPath();
  wxString key;
  