public static ASTNode createLiteralNode(PsiManager manager, String content) {
    final PsiFileFactory f = PsiFileFactory.getInstance(manager.getProject());
    final RncFile file = (RncFile)f.createFileFromText("dummy.rnc", RncFileType.getInstance(), "include \"" + content + "\"");

    final ASTNode include = findFirstGrammarNode(file);
    final ASTNode literal = include.findChildByType(RncTokenTypes.LITERAL);
    assert literal != null;
    return literal;
  }
public static ASTNode createLiteralNode(PsiManager manager, String content)