docs: update vimdocs

Author: github-actions[bot]

doc/copilot.txt

@@ -159,7 +159,7 @@ Default configuration ~
       },
       copilot_node_command = 'node', -- Node.js version must be > 20
       workspace_folders = {},
-      copilot_model = "",  -- Current LSP default is gpt-35-turbo, supports gpt-4o-copilot
+      copilot_model = "",
       root_dir = function()
         return vim.fs.dirname(vim.fs.find(".git", { upward = true })[1])
       end,