nixos: remove optional builtins prefixes from prelude functions

Remove optional builtins prefixes from prelude functions by running:

    builtins=(
      abort
      baseNameOf
      break
      derivation
      derivationStrict
      dirOf
      false
      fetchGit
      fetchMercurial
      fetchTarball
      fetchTree
      fromTOML
      import
      isNull
      map
      null
      placeholder
      removeAttrs
      scopedImport
      throw
      toString
      true
    )

    fd \
      --exclude doc/manual/release-notes \
      --type file \
      . \
      nixos \
      --exec-batch sed --in-place --regexp-extended "
        s/\<builtins\.($(
          printf '%s\n' "${builtins[@]}" |
            paste --delimiter '|' --serial -
        ))\>/\1/g
      "

    nix fmt

nixos/modules/programs/bash/undistract-me.nix

@@ -27,7 +27,7 @@ in
 
   config = lib.mkIf cfg.enable {
     programs.bash.promptPluginInit = ''
-      export LONG_RUNNING_COMMAND_TIMEOUT=${builtins.toString cfg.timeout}
+      export LONG_RUNNING_COMMAND_TIMEOUT=${toString cfg.timeout}
       export UDM_PLAY_SOUND=${if cfg.playSound then "1" else "0"}
       . "${pkgs.undistract-me}/etc/profile.d/undistract-me.sh"
     '';