Fix fish-ism in nixup

bin/,nixup

@@ -4,6 +4,6 @@ SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 
 pushd $SCRIPT_DIR/../nix &> /dev/null
 home-manager switch --flake ".#std"
-if type -q doom; then
+if which doom; then
     doom env
 fi