Official tree-sitter grammar for Logstash config language

[tree-sitter](https://tree-sitter.github.io/tree-sitter/) is a popular backend facility for certain code editors (e.g. [Neovim](https://github.com/nvim-treesitter/nvim-treesitter)) to provide syntax highlighting and other language-specific features.

It would be nice if there were an official grammar for Logstash. There are [some attempts by various individuals](https://github.com/search?q=logstash%20tree-sitter&type=repositories), but it's unclear what the quality or support level for these would be.