nvim: after/ftplugin/c: Do not add include files to buffer list

Hide header files from /usr/include from the buffer list.

nvim/.config/nvim/after/ftplugin/c.lua

@@ -7,3 +7,10 @@ vim.bo.makeprg = 'meson compile -C build'
 
 vim.keymap.set('n', 'gh', ":ClangdSwitchSourceHeader<CR>", { noremap=true, buffer=0 })
 vim.keymap.set('n', 'gq', ":!gst-indent %<CR>"           , { noremap=true, buffer=0 })
+
+vim.api.nvim_create_autocmd({ "BufReadPre", "BufWinEnter" }, {
+  pattern  = { "*/usr/include/*" },
+  callback = function()
+    vim.bo.buflisted = false
+  end,
+})