feat(stages): pass buffer

See #99

Author: rcarriga

README.md

@@ -233,6 +233,7 @@ The function is given a state table that contains the following keys:
   - `width` Width of the message buffer
   - `height` Height of the message buffer
 - `open_windows: integer[]` List of all window IDs currently showing messages
+- `buffer: integer` The buffer containing the rendered notification message.
 
 If a notification can't be shown at the moment the function should return `nil`.
 

lua/notify/windows/init.lua

@@ -216,6 +216,7 @@ function WindowAnimator:get_goals()
   for win, win_stage in pairs(self.win_stages) do
     local notif_buf = self.notif_bufs[win]
     local win_goals = self.stages[win_stage]({
+      buffer = notif_buf:buffer(),
       message = self._get_dimensions(notif_buf),
       open_windows = open_windows,
     }, win)