Fix the reference to the GitHubAPI.graphql documentation in the changelog (#130)
Fix the reference to the GitHubAPI.graphql documentation in the changelog (#130)

It was missing a colon at the front of `:func:`
I've changed it to :meth:`gidgethub.abc.GitHubAPI.graphql` to be consistent with what was written in the previous changelog entry (v4.0.0)
brettcannon/gidgethub,brettcannon/gidgethub