Issue Summary

The return type of .webp images in source view or pr page is incorrect because of this Safari is not able to render it correctly

Steps to Reproduce

Either add a webp to the repository or add as a attachment to a comment on a PR

Expected Results

The return type for the webp attachment should be `image/webp`

Actual Results

The return type for the webp attachment is `audio/x-wav`

Workaround

N/A