Wrap nushell integration script in a module

This prevents the completion command "nu-complete __zoxide_z" from
polluting the command namespace.

templates/nushell.txt

@@ -1,11 +1,13 @@
-{%- let section = "# =============================================================================\n#" -%}
+{%- let section = "# =============================================================================" -%}
 {%- let not_configured = "# -- not configured --" -%}
 
 # Code generated by zoxide. DO NOT EDIT.
 
+module zoxide_integration {
   const homedir = if $nu.home-dir? != null { $nu.home-dir } else { $nu.home-path }
 
   {{ section }}
+  #
   # Hook configuration for zoxide.
   #
 
@@ -54,6 +56,7 @@ export-env {
   {%- endif %}
 
   {{ section }}
+  #
   # Completion for __zoxide_z
   #
 
@@ -84,6 +87,7 @@ def "nu-complete __zoxide_z" [context: string] {
   }
 
   {{ section }}
+  #
   # When using zoxide with --no-cmd, alias these internal functions as desired.
   #
 
@@ -112,6 +116,7 @@ export def --env --wrapped __zoxide_zi [...rest: string] {
   }
 
   {{ section }}
+  #
   # Commands for zoxide. Disable these using --no-cmd.
   #
 
@@ -126,8 +131,12 @@ export alias {{cmd}}i = __zoxide_zi
   {{ not_configured }}
 
   {%- endmatch %}
+}
+
+export use zoxide_integration *
 
 {{ section }}
+#
 # Add this to your env file (find it by running `$nu.env-path` in Nushell):
 #
 #   zoxide init nushell | save -f ~/.zoxide.nu