fix: set mode for all keymaps

plugins/heirline.nix

@@ -160,6 +160,7 @@
 
     keymaps = [
       {
+        mode = "n";
         key = "<leader>bb";
         options.desc = "Select buffer from tabline";
 
@@ -170,6 +171,7 @@
         '';
       }
       {
+        mode = "n";
         key = "<leader>bd";
         options.desc = "Close buffer from tabline";
 
@@ -182,6 +184,7 @@
         '';
       }
       {
+        mode = "n";
         key = "<leader>b\\";
         options.desc = "Horizontal split buffer from tabline";
 
@@ -195,6 +198,7 @@
         '';
       }
       {
+        mode = "n";
         key = "<leader>b|";
         options.desc = "Vertical split buffer from tabline";