tree-sitter is a great tool to have an incremental syntax tree of our code, in emacs it can be used to add syntax highlighting instead of using the regular regex based highlighting system. There are other use cases for this and now we're going to use it to build a simple tool to run ispell using the content of a text node, of course we can select the text manually but it will be easier and fancy to do it in a programmatic way using the syntax tree generated by tree-sitter.