[NOTICE] Add warning about tree-sitter branch becoming master soon.

Author: kristijanhusak

README.md

@@ -16,8 +16,10 @@
 
 ## Tree-sitter
 Tree-sitter support branch: https://github.com/kristijanhusak/orgmode.nvim/tree/tree-sitter
-#### NOTE: tree-sitter branch will become main very soon! 
-All new features and fixes are going to the `tree-sitter` branch.
+#### Tree-sitter branch will become main very soon!
+To remove warning message, you can do two things:
+1. Temporarily switch to the [tree-sitter](https://github.com/kristijanhusak/orgmode.nvim/tree/tree-sitter) branch
+2. Stay on master branch and install [nvim-treesitter](https://github.com/nvim-treesitter/nvim-treesitter) and [tree-sitter-org grammar](https://github.com/milisims/tree-sitter-org). More info here: https://github.com/kristijanhusak/orgmode.nvim/tree/tree-sitter#setup.
 
 ## Installation
 

lua/orgmode/init.lua

@@ -14,6 +14,7 @@ function Org:new()
   setmetatable(data, self)
   self.__index = self
   data:setup_autocmds()
+  vim.defer_fn(data.notify_update, 200)
   return data
 end
 
@@ -47,6 +48,18 @@ function Org:setup_autocmds()
   vim.cmd([[augroup END]])
 end
 
+function Org:notify_update()
+  local success, _ = pcall(vim.treesitter.inspect_language, 'org')
+  if success then
+    return
+  end
+  local msg = {
+    '[orgmode] Master branch will soon require tree-sitter support.',
+    'To remove this message, see https://github.com/kristijanhusak/orgmode.nvim/tree/master#tree-sitter.',
+  }
+  vim.notify(table.concat(msg, '\n'), vim.log.levels.WARN)
+end
+
 ---@param opts? table
 ---@return Org
 local function setup(opts)