SCREAMING-KEBAB-CASE support

[greyblake]

Hey! Thanks for the nice library =)

Here is a small patch for support of SCREAMING-KEBAB-CASE, that is used in some APIs. Name is inspired by already existing SCREAMING_SNAKE_CASE and kebab-case.

[dtolnay]

Thanks! The implementation looks good to me.

Could you point out any public-facing APIs that use this convention? I have never seen this before.

[greyblake]

@dtolnay Hey! The one that I am interesting in is Bittrex API.
Example: https://bittrex.com/api/v1.1/public/getmarketsummaries
I agree, it may look weird, but they use market names like BTC-LTC, BTC-ETH, etc. So I thought it would be good to have something like SCREAMING-KEBAB-CASE to parse market names into enum automatically.

[dtolnay]

Thanks for the review @clarcharr. I removed the comments because I don't care about formatting in PRs -- see #438 (comment) for my philosophy.

@greyblake those are values in the JSON, not keys, so to clarify are you deserializing into something like this?

#[derive(Deserialize)]
#[serde(rename_all = "PascalCase")]
struct Summary {
    market_name: MarketName,
    /* other fields */
}

#[derive(Deserialize)]
#[serde(rename_all = "SCREAMING-KEBAB-CASE")]
enum MarketName {
    BtcLtc,
    BtcEth,
}

[greyblake]

@dtolnay Yes, those are values. The example you provided is exactly what I do in my code base.