fix(#2154): find_file doesn't work when group_empty option is enabled (#2100)

Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/renderer/builder.lua

@@ -341,6 +341,8 @@ function Builder:_build_line(node, idx, num_children, unloaded_bufnr)
 
   self.index = self.index + 1
 
+  node = require("nvim-tree.lib").get_last_group_node(node)
+
   if node.open then
     self.depth = self.depth + 1
     self:build(node, unloaded_bufnr)