[gatsby-source-contentful] odd nesting of "LongText" field types...

Description

hi there 👋 thanks for the awesome lib! 👏👍

something i ran in to recently: i’m getting oddly nested / awkward graphQL data - ex: node.title.title (vs. node.title) after syncing with the contentful API.

Environment

Gatsby version: v1.9.127 Node.js version: v8.9.3 Operating System: macOS 10.12.6

Actual result

given an api response from https://cdn.contentful.com like:

{
    "sys": {
        "space": {
            "sys": {
                "type": "Link",
                "linkType": "Space",
                "id": "..."
            }
        },
        "id": "1ywsMB0CakekKucSkUS6Ee",
        "type": "Entry",
        "createdAt": "2017-12-11T19:54:49.991Z",
        "updatedAt": "2017-12-13T22:18:58.292Z",
        "revision": 6,
        "contentType": {
            "sys": {
                "type": "Link",
                "linkType": "ContentType",
                "id": "page"
            }
        },
        "locale": "en-US"
    },
    "fields": {
        "name": "whitepapers",
        "title": "Whitepapers",
        ...
    }

}

and a graphQL query like:

{
    allContentfulPage {
        edges {
            node {
                id
                name
                title {
                    title
                }
            }
        }
    }
}

i end up with data like:

{
    "data": {
        "allContentfulPage": {
            "edges": [
                {
                    "node": {
                        "id": "c1ywsMB0CakekKucSkUS6Ee",
                        "name": "whitepapers",
                        "title": {
                            "title": "Whitepapers",
                        }
                    }
                }
            ]
        }
    }
}

note the difference between the name and title fields. in contentful, “name” is a ShortText field while “title” is LongText

Expected behavior

ideally, both “name” and "title would be represented in the same way - that is, like the “name” data, un-nested (instead of node.title.title, just plain old node.title)

Steps to reproduce

1. configure gatsby-source-contentful to point to a recently populated space & content model

2. run gatsby develop

3. visit http://localhost:8000/___graphql and query your data

[KyleAMathews]

This is deliberate — long text fields are markdown so to be able to easily compile those, this field type is created as a child node so then gatsby-transformer-remark can compile it to HTML e.g. https://github.com/gatsbyjs/gatsby/blob/971c4af38a588cd54c18cb9645d60d50856fd9ea/examples/using-contentful/src/templates/product.js#L72

The source plugins still exposes the raw markdown but generally you’d want to use the transformed HTML as in the above code sample.

[jserrao]

@KyleAMathews - it would make good sense to add this information into https://www.npmjs.com/package/gatsby-source-contentful and the Gatsby 2.0 docs. This took me hours to figure out.