fix(plugin): allow command chaining with bar separator (#29)

Problem: :Pending|only failed because the command definition lacked the
bar attribute, causing | to be consumed as an argument.

Solution: Add bar = true to nvim_create_user_command so | is treated as
a command separator, matching fugitive's :Git behavior.

plugin/pending.lua

@@ -6,6 +6,7 @@ vim.g.loaded_pending = true
 vim.api.nvim_create_user_command('Pending', function(opts)
   require('pending').command(opts.args)
 end, {
+  bar = true,
   nargs = '*',
   complete = function(arg_lead, cmd_line)
     local subcmds = { 'add', 'sync', 'archive', 'due', 'undo' }