"according to the GraphQL spec" points to a wrong url

[CSalih]

Description

The anchor link "according to the GraphQL spec" points to http://facebook.github.io/graphql/#sec-Data but this page does not exists anymore.

Steps to Reproduce

1. Go to: https://graphql.org/learn/serving-over-http/#response
2. Click on according to the GraphQL spec

Expected Result

The page should be shown

Actual Result

The page will not be shown (Status code 404)

Additional Context

[Urigo]

thanks! could you submit a PR with a fix?

[CSalih]

Hi @Urigo, i prepared a PR with a fix for this page.
I found a another broken GraphQL link in a blog post (https://github.com/graphql/graphql.github.io/blob/source/src/content/blog/2015-09-14-graphql.md) should i fix this as well? I can create another PR for the second broken link or put it into #1410.

[Urigo]

@CSalih thank you!
Just merged, can you please open a new PR with the other fixes?
Thanks!