fix: load plugin/ in autocmds before 'loadplugins'

Fix #33

lua/pckr/loader.lua

@@ -163,8 +163,10 @@ local function packadd(plugin, bang)
     return
   end
 
-  if vim.v.vim_did_enter == 0 and bang then
+  -- Use vim.g.loaded_pckr as a signal for then plugin/* is loaded.
+  if not vim.g.loaded_pckr and bang then
     -- Do not source. We've already added to rtp, so no need to do anything.
+    -- Do not load plugin/* as that will be done by 'loadplugins' later.
     return
   end
 

plugin/pckr.lua

@@ -1,3 +1,8 @@
+if not vim.g.loaded_pckr then
+  return
+end
+
+vim.g.loaded_pckr = true
 
 vim.api.nvim_create_user_command(
   'Pckr',