fix: opening "nvim dir/" may focus wrong window

Yazi.nvim has a feature where you can specify `open_for_directories =
true` to automatically open yazi when opening a directory in Neovim.

In some cases, opening a directory when starting Neovim from the command
line would show yazi, but the window under yazi was selected. Yazi was
supposed to have been focused instead.

This was due to the default netrw file manager not having a file name
for the buffer that was opened. I don't know why this only happened in
some cases.

Fixes #58

.gitignore

@@ -5,4 +5,3 @@ scripts/lazy.nvim/
 /luarocks
 /lua_modules
 /.luarocks
-/lua

lua/yazi.lua

@@ -128,7 +128,10 @@ function M.setup(opts)
     -- When opening neovim with "nvim ." or "nvim <directory>", the current
     -- buffer is already open at this point. If we have already opened a
     -- directory, display yazi instead.
-    open_yazi_in_directory(vim.fn.expand('%:p'), vim.api.nvim_get_current_buf())
+    open_yazi_in_directory(
+      vim.b.netrw_curdir or vim.fn.expand('%:p'),
+      vim.api.nvim_get_current_buf()
+    )
   end
 end