Remove unnecessary dag variables

Also remove a few trailing whitespaces.

modules/programs/msmtp.nix

@@ -6,8 +6,6 @@ let
 
   cfg = config.programs.msmtp;
 
-  dag = config.lib.dag;
-
   msmtpAccounts = filter (a: a.msmtp.enable)
     (attrValues config.accounts.email.accounts);
 

modules/programs/notmuch.nix

@@ -4,8 +4,6 @@ with lib;
 
 let
 
-  dag = config.lib.dag;
-
   cfg = config.programs.notmuch;
 
   mkIniKeyValue = key: value:
@@ -24,12 +22,12 @@ let
         database = {
           path = config.accounts.email.maildirBasePath;
         };
-    
+
         new = {
           ignore = cfg.new.ignore;
           tags = cfg.new.tags;
         };
-    
+
         user =
           let
             accounts =
@@ -42,7 +40,7 @@ let
             primary_email = catAttrs "address" primary;
             other_email = catAttrs "address" secondaries;
           };
-    
+
         search = {
           exclude_tags = [ "deleted" "spam" ];
         };
@@ -168,7 +166,7 @@ in
               export PATH="${pkgs.notmuch}/bin''${PATH:+:}$PATH"
               export NOTMUCH_CONFIG="${config.xdg.configHome}/notmuch/notmuchrc"
               export NMBGIT="${config.xdg.dataHome}/notmuch/nmbug"
-    
+
               ${cmds}
             '';
             executable = true;

modules/services/polybar.nix

@@ -6,8 +6,6 @@ let
 
   cfg = config.services.polybar;
 
-  dag = config.lib.dag;
-
   toPolybarIni = generators.toINI {
     mkKeyValue = key: value:
       let

modules/services/window-managers/i3.nix

@@ -6,8 +6,6 @@ let
 
   cfg = config.xsession.windowManager.i3;
 
-  dag = config.lib.dag;
-
   commonOptions = {
     fonts = mkOption {
       type = types.listOf types.string;

modules/services/window-managers/xmonad.nix

@@ -6,8 +6,6 @@ let
 
   cfg = config.xsession.windowManager.xmonad;
 
-  dag = config.lib.dag;
-
   xmonad = pkgs.xmonad-with-packages.override {
     ghcWithPackages = cfg.haskellPackages.ghcWithPackages;
     packages = self: