getComment method
Fetches the specified issue comment.
API docs: https://developer.github.com/v3/issues/comments/#get-a-single-comment
Implementation
Future<IssueComment> getComment(RepositorySlug slug, int id) =>
github.getJSON('/repos/${slug.fullName}/issues/comments/$id',
convert: (dynamic i) => IssueComment.fromJson(i));