Bump clap to version 4.0

[tranzystorekk]

I'm back 😊

Clap 4 drops the indexmap dependency, which is presumably good for the compile time.

I also reformatted the longer help descriptions so they are cut off in short help mode jless -h, while also are printed in a more redable form for jless --help

[PaulJuliusMartinez]

I ended up doing this in cf8d48b because I wanted to use ArgAction. No idea if I actually needed to upgrade, but the random blog post I copied from used 4.0, so I just went with it. I just opened this up and reapplied all the changes, so you definitely saved me at least 15-30 minutes. Thanks.