Add section with command-line tool command documentation.

Add tool to generate command-line tool command documentation.

Remove the `snap` section, since this is no longer maintained.

Tweak README file

Bumps [github.com/onsi/ginkgo/v2](https://github.com/onsi/ginkgo) from 2.22.2 to 2.23.0.
- [Release notes](https://github.com/onsi/ginkgo/releases)
- [Changelog](https://github.com/onsi/ginkgo/blob/master/CHANGELOG.md)
- [Commits](onsi/ginkgo@v2.22.2...v2.23.0)

---
updated-dependencies:
- dependency-name: github.com/onsi/ginkgo/v2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [golang.org/x/tools](https://github.com/golang/tools) from 0.30.0 to 0.31.0.
- [Release notes](https://github.com/golang/tools/releases)
- [Commits](golang/tools@v0.30.0...v0.31.0)

---
updated-dependencies:
- dependency-name: golang.org/x/tools
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [golang.org/x/net](https://github.com/golang/net) from 0.36.0 to 0.37.0.
- [Commits](golang/net@v0.36.0...v0.37.0)

---
updated-dependencies:
- dependency-name: golang.org/x/net
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

…ub.com/onsi/ginkgo/v2-2.23.0

Bump github.com/onsi/ginkgo/v2 from 2.22.2 to 2.23.0

…ng.org/x/tools-0.31.0

Bump golang.org/x/tools from 0.30.0 to 0.31.0

…ng.org/x/net-0.37.0

Bump golang.org/x/net from 0.36.0 to 0.37.0

Fixes: #448

Use `err.Error()` of `ExitCode` interface since this has a nil check.

Move `ExitCode` into its own source file.

Fix TYPO in comment about error.

Fix panic when exit code does not have a cause