feat: enable Nerd Font and add supermaven plugin support

lua/custom/plugins/supermaven.lua

@@ -0,0 +1,13 @@
+return {
+  {
+    'supermaven-inc/supermaven-nvim',
+
+    config = function()
+      require('supermaven-nvim').setup {
+        color = {
+          suggestion_color = '#ffffff',
+        },
+      }
+    end,
+  },
+}