feat: add before and after callbacks

lua/persisted/config.lua

@@ -6,6 +6,8 @@ local defaults = {
   use_git_branch = false, -- create session files based on the branch of the git enabled repository
   autosave = true, -- automatically save session files
   options = { "buffers", "curdir", "tabpages", "winsize" }, -- session options used for saving
+  before_save = function() end, -- function to run before the session is saved to disk
+  after_save = function() end, -- function to run after the session is saved to disk
 }
 
 ---@type PersistedOptions

lua/persisted/init.lua

@@ -64,11 +64,15 @@ function M.stop()
 end
 
 function M.save()
+  config.options.before_save()
+
   local tmp = vim.o.sessionoptions
   vim.o.sessionoptions = table.concat(config.options.options, ",")
   vim.cmd("mks! " .. e(M.get_current()))
   vim.o.sessionoptions = tmp
   vim.g.persisting = true
+
+  config.options.after_save()
 end
 
 function M.delete()