We're somewhat limited by what version of clap is available in our internal monorepo. We try to keep things reasonably up-to-date though, so I'm sure we'll upg

We're somewhat limited by what version of clap is available in our internal monorepo. We try to keep things reasonably up-to-date though, so I'm sure we'll upgrade at some point. I believe we actually only use clap for some side binaries, not for the main sl executable. We have a custom parser for that (https://github.com/facebook/sapling/tree/main/eden/scm/lib/cliparser/src https://github.com/facebook/sapling/tree/main/eden/scm/lib/c...), to match the preexisting hg parse behavior. Unfortunately I'm not familiar enough with clap or why we didn't go with clap in the first place to say what we would need to use clap for the main binary.