Format lazy_static! macro

Format lazy_static! macro

Some macros like `lazy_static!` cannot be parsed as a valid AST. Therefore, we
need to parse them manually to be able to format them. Obviously this method
will not scale, we will never be able to cover every macro in the entire
ecosystem. That being said, I think it will not hurt to be able to format macros
that are popular (such as `lazy_static!`) as long as rustfmt will not produce
broken code when the macro has syntax that is not expected.