[Postgres Create Function]: does not support `$$`

[zidaye]

fn test() {
    let sql = "CREATE OR REPLACE FUNCTION increment(i INTEGER) RETURNS INTEGER  LANGUAGE plpgsql AS $$ BEGIN RETURN i + 1; END; $$;";

    let dialect = PostgreSqlDialect {};
    let ast = Parser::parse_sql(&dialect, sql).unwrap();
    println!("AST: {:?}", ast);
}

The result after the test case is executed：

panicked at 'called `Result::unwrap()` on an `Err` value: ParserError("Expected literal string, found: $")', examples/parse_select.rs:23:48