net/http: DetectContentType: add audio/amr signature

[OneOfOne]

The signature for that audio file type is missing.

[OneOfOne]

https://go-review.googlesource.com/c/go/+/400174

[gopherbot]

Change https://go.dev/cl/400174 mentions this issue: net/http: DetectContentType: add audio/amr signature

[neild]

https://mimesniff.spec.whatwg.org/#matching-an-audio-or-video-type-pattern doesn't include a pattern for audio/amr.

[OneOfOne]

@neild I'd like to argue that it's a popular enough format in the mobile world specially with older headsets that it warrants support.

[neild]

We don't really want to be in the business of making judgments about what is popular enough or not. DetectContentType is documented as following the WHATWG algorithm; the way to add a new type is to convince WHATWG to add it.