`require-copyright-header` should insert as first comment

[kerryarchibald]

Describe the bug
In files with a comment before any statements or imports,require-copyright-header --fix inserts the header after the first comment.
Eg:
https://github.com/matrix-org/matrix-react-sdk/pull/8514/files/be114d0f6fb571c2a729f771b6e0afe76f90ea20#diff-8a7f360d167712620cbea8af174842a1dd85be4bf184e627c7f054bbea162bb4

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
copyright header should be inserted as the first comment in the file

[stanj98]

Hey, are you currently undertaking this issue?