docs(website): update edit layer doc

docs/layers/edit.md

@@ -30,3 +30,27 @@ This layer provides many edit key bindings for SpaceVim, and also provides more
 ## Options
 
 - `textobj`: specified a list of text objects to be enabled, the avaliable list is :`indent`, `line`, `entire`
+- `autosave_timeout`: set the timeoutlen of autosave plugin. By default it
+is 0. And autosave is disabled. timeoutlen must be given in millisecods and
+can't be > 100*60*1000 (100 minutes) or < 1000 (1 second). For example,
+setup timer with 5 minutes:
+  ```
+  [[layers]]
+    name = 'edit'
+    autosave_timeout = 300000
+  ```
+- `autosave_events`: set the events on which autosave will perform a save.
+This option is an empty list by default. you can trigger saving based
+on vim's events, for example:
+  ```
+  [[layers]]
+    name = 'edit'
+    autosave_events = ['InsertLeave', 'TextChanged']
+  ```
+- `autosave_all_buffers`: By default autosave plugin only save current buffer.
+If you want to save all buffers automatically. Set this option to `true`.
+  ```
+  [[layers]]
+    name = 'edit'
+    autosave_all_buffers = true
+  ```