make nushell init script more idiomatic

templates/nushell.txt

@@ -39,13 +39,14 @@ if (not ($env | default false __zoxide_hooked | get __zoxide_hooked)) {
 #
 
 # Jump to a directory using only keywords.
-def --env --wrapped __zoxide_z [...rest:string] {
-  let arg0 = ($rest | append '~').0
-  let arg0_is_dir = (try {$arg0 | path expand | path type}) == 'dir'
-  let path = if (($rest | length) <= 1) and ($arg0 == '-' or $arg0_is_dir) {
-    $arg0
-  } else {
-    (zoxide query --exclude $env.PWD -- ...$rest | str trim -r -c "\n")
+def --env --wrapped __zoxide_z [...rest: string] {
+  let path = match $rest {
+    [] => {'~'},
+    [ '-' ] => {'-'},
+    [ $arg ] if ($arg | path type) == 'dir' => {$arg}
+    _ => {
+      zoxide query --exclude $env.PWD -- ...$rest | str trim -r -c "\n"
+    }
   }
   cd $path
 {%- if echo %}