feat: add TOON parser support

Add tree-sitter grammar for TOON (Token-Oriented Object Notation),
a JSON-alternative data format with indentation-based structure.

- Add parser config in parsers.lua
- Add query files: highlights, folds, indents, locals

Parser repository: https://github.com/DanEscher98/tree-sitter-toon
TOON spec: https://github.com/toon-format/spec

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

lua/nvim-treesitter/parsers.lua

@@ -2434,6 +2434,15 @@ list.toml = {
   maintainers = { "@tk-shirasaka" },
 }
 
+list.toon = {
+  install_info = {
+    url = "https://github.com/DanEscher98/tree-sitter-toon",
+    files = { "src/parser.c", "src/scanner.c" },
+    branch = "main",
+  },
+  maintainers = { "@DanEscher98" },
+}
+
 list.tsv = {
   install_info = {
     url = "https://github.com/amaanq/tree-sitter-csv",