feat(treesj.lua): add treesj plugin configuration

Add a new file `treesj.lua` to the `absolute/plugins` directory. The file contains the configuration for the `treesj` plugin. The plugin is sourced from the repository `Wansmer/treesj` and has a dependency on `nvim-treesitter/nvim-treesitter`. The configuration includes loading the `absolute.after.treesj` module.

lua/absolute/plugins/treesj.lua

@@ -0,0 +1,7 @@
+return {
+	"Wansmer/treesj",
+	dependencies = { "nvim-treesitter/nvim-treesitter" },
+	config = function()
+        require("absolute.after.treesj")
+    end,
+}