fix(nushell): fully fix config

overlays/derivations/nu/cfg/config.nu

@@ -21,4 +21,4 @@ mkdir ($nu.data-dir | path join "vendor/autoload")
 starship init nu | save -f ($nu.data-dir | path join "vendor/autoload/starship.nu")
 zoxide init nushell | save -f ($nu.data-dir | path join "vendor/autoload/zoxide.nu")
 
-alias nos = "nh os"
+alias nos = nh os

overlays/derivations/nu/cfg/env.nu

@@ -17,8 +17,7 @@
 # You can remove these comments if you want or leave
 # them for future reference.
 
-$env = {
-  config = {
+$env.config = {
   hooks: {
     pre_prompt: [{ ||
       if (which direnv | is-empty) {
@@ -35,6 +34,4 @@ $env = {
     mode = "heavy"
   }
   show_banner: false
-  }
-  LS_COLOURS = ""
 }