chore: transform noisy files in e2e migration test (#1146)

## PR Checklist

- [x] Addresses an existing open issue: fixes #1142
- [x] That issue was marked as [`status: accepting
prs`](https://github.com/JoshuaKGoldberg/create-typescript-app/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in
[CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/create-typescript-app/blob/main/.github/CONTRIBUTING.md)
were taken

## Overview

In the migration script, after running with `--mode migrate` but before
running test assertions, modifies a couple of files on disk:

1. `.all-contributorsrc`: Formats with `JSON.stringify(..., null, 2)` as
it seems All Contributors isn't able to use Prettier for it
2. `.github/DEVELOPMENT.md`: Adds back in the `## The Setup Scripts`
heading, as it's not part of the default template

Also wraps the `test`s in `describe` and standardizes naming just a bit.
I'm very nitpicky.