@Nullable
  private static Language getLanguage(@NotNull Project project, @NotNull DiffContent content) {
    Language language = content.getUserData(DiffUserDataKeys.LANGUAGE);
    if (language != null) return language;

    FileType fileType = content.getContentType();
    VirtualFile file = content instanceof DocumentContent ? ((DocumentContent)content).getHighlightFile() : null;
    if (file != null) {
      return ReadAction.compute(() -> LanguageUtil.getLanguageForPsi(project, file, fileType));
    }
    return fileType == null ? null : LanguageUtil.getFileTypeLanguage(fileType);
  }
@Nullable
  private static Language getLanguage(@NotNull Project project, @NotNull DiffContent content)