Setting up tree-sitter

The tree-sitter grammar gives editors highlighting, folding and indentation that understand M2’s actual syntax.

You may not need this at all:

• VS Code: the extension gets highlighting from the language server, nothing to set up.
• Any editor running m2-ls: semantic highlighting from the server already covers most of what tree-sitter would. Tree-sitter adds instant highlighting before the server starts, folding and indentation.