vim-indent-guides doesn't work on Neovim 0.10.x (on macOS)

[gslin]

After crosschecking with multiple environments, I found vim-indent-guides not working under certain environments:

• Neovim 0.10.1 (installed with Homebrew, current latest, on macOS 14.6.1)
• Neovim 0.10.0 (installed with Homebrew, downgraded, on macOS 14.6.1)

But it's working on older Neovim:

• Neovim 0.9.5 (installed with Homebrew, downgraded, on macOS 14.6.1)

Also, it's working on vim:

• Vim 9.1.650 (installed with Homebrew, current latest, on macOS 14.6.1)

On Linux it's working too, due to much older versions:

• Neovim 0.7.2 (installed with PPA, https://launchpad.net/~neovim-ppa/+archive/ubuntu/stable, on Ubuntu 22.04)
• Vim 8.2.2121 (installed with Ubuntu official APT repository, on Ubuntu 22.04)

My .vimrc can be reviewed from https://github.com/gslin/config/blob/master/.vim/vimrc this url.