Maintain comments when parsing schema

```graphql
type GlobalCinemaVenue implements Node @preLoad {
# @todo Refactor into a dynamic set of identifiers, i.e.
"""
https://webediamoviespro.com identifier.
"""
foreignWebediaId: String
}

```

Currently when using `parse`, the `@todo Refactor into a dynamic set of identifiers, i.e.` is not made available in AST. As a result, this data is lost when implementing utilities for formatting SDL, e.g. https://github.com/gajus/sort-graphql-sdl.

It would be nice if there was a way to parse/ print SDL while maintaining comments and descriptions.