Add ability to provide query description for fulltext and vector queries

[darrellwarde]

I would like to be able to provide API documentation for my fulltext and vector queries, preferably in their respective directives. For example:

type Movie @node @fulltext(indexes: [{ queryName: "moviesByTitle", queryDescription: "This query can be used to search for movies by title", fields: ["title"], indexName: "moviesByTitle" }]) {
    title: String!
}

In the output GraphQL, this would be put as the field description:

type Query {
    """
    This query can be used to search for movies by title
    """
    moviesByTitle: MoviesIndexConnection!
}