This is a sweet idea, thank you!

My suggestion for minimal/readable:

  /*usr/bin/env go run "$0" "$@"; exit;*/

  - go fmt leaves it alone
  - it preserves the exit code in case env or go breaks
  - it "figures out" where go is, no need to hard code a path that breaks on yet another machine (where /usr/bin/env is "standard")

  ( 
  The first example:
  - I'm not a big fan of the subtle extra work that the question mark in the original path imposes on the system.  env is (almost) always going to be as /usr/bin/env and rarely would something else that matches exist.  ls -d /?sr to see what outputs on your system.  That being said, the extra work isn't very meaningful in this case...

  - The trailing $? seems unnecessary as the final exit will convey the return code from env go regardless of if the $? is present or not
  )