ftdetect files under rtp aren't sourced

[dancek]

Not sure if I'm overlooking something obvious – sorry if I'm wasting your time here!

• nvim --version: 0.8.0
• git --version: 2.38.1
• Operating system/version: Arch Linux (rolling release, updated this month)
• Terminal name/version: kitty 0.26.5

Steps to reproduce

1. Add the following lines in plugins.lua:

  use {
    'mlochbaum/BQN',
    rtp = 'editors/vim/'
  }

2. Run PackerCompile and PackerSync, exit Neovim
3. touch test.bqn
4. nvim test.bqn

Actual behaviour

Filetype is not bqn (instead it tends to be conf for actual BQN files but empty for empty files). However if filetype is set manually the plugin works.

Expected behaviour

Filetype should be bqn. The file https://github.com/mlochbaum/BQN/blob/master/editors/vim/ftdetect/bqn.vim should have been loaded.

packer files

Plugin specification file(s)

The steps above should be enough

packer log file

No lines in log when opening file

packer compiled file

Relevant snippets:

_G.packer_plugins = {
  BQN = {
    loaded = true,
    path = "/home/hannu/.local/share/nvim/site/pack/packer/start/BQN/editors/vim/",
    url = "https://github.com/mlochbaum/BQN"
  },

-- Runtimepath customization
time([[Runtimepath customization]], true)
vim.o.runtimepath = vim.o.runtimepath .. ",/home/hannu/.local/share/nvim/site/pack/packer/start/BQN/editors/vim/"
time([[Runtimepath customization]], false)