feat: option to quite vim if oil is closed as last buffer (#491)

* feat: auto-quit vim if oil is closed as last buffer

* rename auto_close_vim to auto_close_last_buffer

* rework actions.close to be more like actions.cd

* fix: configure close action correctly

* add type annotation, future proofing

* fix: typo

* fix: typo

* refactor: better type annotations and backwards compatibility

---------

Co-authored-by: Steven Arcangeli <506791+stevearc@users.noreply.github.com>

lua/oil/actions.lua

@@ -143,7 +143,16 @@ M.parent = {
 
 M.close = {
   desc = "Close oil and restore original buffer",
-  callback = oil.close,
+  callback = function(opts)
+    opts = opts or {}
+    oil.close(opts)
+  end,
+  parameters = {
+    exit_if_last_buf = {
+      type = "boolean",
+      desc = "Exit vim if oil is closed as the last buffer",
+    },
+  },
 }
 
 ---@param cmd string