bug: Keymaps from expanded groups only show one key

[sid-6581]

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• I have read all the which-key.nvim docs
• I have updated the plugin to the latest version before submitting this issue
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• I have searched the existing issues of plugins related to this issue

Neovim version (nvim -v)

latest nightly

Operating system/version

Windows 11

Describe the bug

With the repro below, I get the following:

There are multiple keymaps with the same key that are from expanded groups. Instead of showing the entire key combo, it's only showing the last one.

Steps To Reproduce

Use the repro below and do :WhichKey

Expected Behavior

The entire key combo for items from expanded groups.

Health

No response

Log

No response

Repro

vim.env.LAZY_STDPATH = ".repro"
load(vim.fn.system("curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua"))()

require("lazy.minit").repro({
  spec = {
    { "folke/which-key.nvim", opts = {
        expand = function(_node)
          return true
        end,
    } },
  },
})