* refactor powershell setup to make it sourceable
* only set editor if it is unset
* change directory to spack root in subshell
* Update share/spack/setup-env.ps1
Co-authored-by: John W. Parent <45471568+johnwparent@users.noreply.github.com>
Co-authored-by: John W. Parent <45471568+johnwparent@users.noreply.github.com>
