fix(emacs): make default application

modules/home/emacs.nix

@@ -129,6 +129,13 @@ in {
         };
     in {
 
+      xdg.mimeApps = {
+        enable = true;
+        associations.defaultApplicationPackages = [
+          sydmacs
+        ];
+      };
+      
       # Set emacsclient as the default editor for the time being.
       home.sessionVariables = {
         EDITOR = "emacsclient";