This fixes running `zed <path>` inside nixos wsl instances. We're
copying the approach used elsewhere which is to try using `--exec`
first, and if that fails use an actual shell which should cover the
nixos case because it only puts binaries on your PATH inside the
`/etc/profile` script which is sourced on shell startup.

Release Notes:

- N/A

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Co-authored-by: John Tur <john-tur@outlook.com>