Add more convert to case commands (#2825)

I'm using [convert_case](https://crates.io/crates/convert_case)
underneath the hood, which has over 35 million downloads and feels
solid.

Release Notes:

- Added commands to convert between variable name styles
([#1821](https://github.com/zed-industries/community/issues/1821)).
    - `convert to kebab case`
    - `convert to snake case`
    - `convert to upper camel case`
    - `convert to lower camel case`
    - `convert to title case`
d1048d03b0Joseph T. Lyons committed on 8/5/2023, 2:51:32 AM· committed by GitHubparents5c2f38a12e8f41
3 files changedLine totals unavailable