`--emit-index-annotation` should redact usernames and passwords in index URL

e.g.

```
# from https://aws:asupersecretpasswordorauthtoken@my-account-123.d.codeartifact.us-west-2.amazonaws.com/pypi/my-private-repo/simple
```
->
```
# from https://my-account-123.d.codeartifact.us-west-2.amazonaws.com/pypi/my-private-repo/simple
```