fix(nvim): use nvim-treesitter.install in favour of :TSInstall

This resolves an issue with it being an unrecognized command for the
initial install.

dot_config/nvim/lua/plugins.lua

@@ -157,7 +157,7 @@ return packer.startup(function(use)
 	-- syntax
 	use({
 		"nvim-treesitter/nvim-treesitter",
-		run = ":TSUpdate",
+		run = function() require('nvim-treesitter.install').update({ with_sync = true }) end,
 		config = function()
 			require("config/treesitter")
 		end,