fix(alpha): replace default buttons with actual keymaps

plugins/ui.nix

@@ -37,5 +37,18 @@
       enable = true;
       theme = "dashboard";
     };
+
+    luaConfigRC.alpha-buttons = ''
+      local dashboard = require("alpha.themes.dashboard")
+      dashboard.section.buttons.val = {
+        dashboard.button("e",    "  New file",           ":ene <BAR> startinsert<CR>"),
+        dashboard.button(",ff",  "  Find file",          ":FzfLua files<CR>"),
+        dashboard.button(",fo",  "  Recently opened",    ":FzfLua oldfiles<CR>"),
+        dashboard.button(",fg",  "  Find word",          ":FzfLua live_grep<CR>"),
+        dashboard.button(",fp",  "  Open session",       ":SessionManager load_session<CR>"),
+        dashboard.button("q",    "  Quit",               ":qa<CR>"),
+      }
+      require("alpha").setup(dashboard.config)
+    '';
   };
 }