Fix kebab-caseificiation

[Baccata]

See https://github.com/disneystreaming/smithy4s/blame/89e88c972174fa0a3b2853901a52a5a6a4662c6d/modules/decline/src/core/commons.scala#L31

Running this on a string that starts with a lowercase erases the first letter.

[plokhotnyuk]

@Baccata Could you please check if following functions pass your requirements then they will save a lot of CPU cycles in runtime: https://github.com/plokhotnyuk/jsoniter-scala/blob/ced2478473c992e99f783faedc132adcf55eed79/jsoniter-scala-macros/shared/src/main/scala-3/com/github/plokhotnyuk/jsoniter_scala/macros/JsonCodecMaker.scala#L484-L560

[Baccata]

@plokhotnyuk thanks :) tbh it's for a rather un-used CLI-derivation module, performances are not really that critical in this context, but I do appreciate the tip !