Pass warn in FromNameLoader.

[reitermarkus]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
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[MikeMcQuaid]

@reitermarkus Can you provide some context on why this is needed? Thanks.

[reitermarkus]

Without it, no rename warning will ever be shown when using this loader.

[MikeMcQuaid]

@reitermarkus Ok, thanks. In future PRs: can you put that context in the body (particularly when using critical to self-merge)? Thanks!