Render Formula/omp.rb with two changes so the formula actually installs:
- Stamp `using: :nounzip` on every per-platform `url` stanza so Homebrew
leaves the downloaded bare Mach-O/ELF asset in the staging CWD; the
default `CurlDownloadStrategy` was routing through
`UnpackStrategy::Uncompressed#extract_nestedly`, nesting the file
outside CWD so `Dir["omp-*"].first` returned `nil` and
`bin.install nil => "omp"` raised.
- Wrap `generate_completions_from_executable` in
`with_env(HOME: buildpath)` so the popened binary's `os.homedir()`
resolves into the writable staging dir instead of the real
`/Users/<user>/.omp`, which Homebrew's sandbox profile denies read
access to.
Also export `renderFormula` (gated by `import.meta.main`) and add a
unit test that pins the rendered stanza shape for future regressions.
Fixes#2398
roboomp