add instructions to setup LSP and tree-sitter in nvim (#8)

Author: gerau

README.md

@@ -30,3 +30,73 @@ cd simplicityhl-lsp
 cargo install --path .
 ```
 
+## Integration with editors
+
+### Neovim
+
+#### LSP
+
+0. Install `simplicityhl-lsp` to your `PATH`.
+
+1. Include this Lua snippet to your Neovim config:
+
+```lua
+vim.filetype.add({
+	extension = {
+		simf = "simf",
+	},
+})
+
+vim.lsp.config["simplicityhl-lsp"] = { cmd = { "simplicityhl-lsp" }, filetypes = { "simf" }, settings = {} }
+vim.lsp.enable("simplicityhl-lsp")
+```
+
+2. Open `.simf` file and check that LSP is active ("attached"):
+
+```vim
+:checkhealth vim.lsp
+```
+
+#### Tree-sitter (Highlighting)
+
+Currently, the Language Server does not provide any syntax highlighting on its own, but you can install tree-sitter for SimplicityHL:
+
+0. Set up the [`nvim-treesitter`](https://github.com/nvim-treesitter/nvim-treesitter/tree/main) plugin.
+
+1. Include this Lua snippet in your Neovim config to register parser:
+
+```lua
+vim.api.nvim_create_autocmd("User", {
+	pattern = "TSUpdate",
+	callback = function()
+		require("nvim-treesitter.parsers").simplicityhl = {
+			install_info = {
+				url = "https://github.com/distributed-lab/tree-sitter-simplicityhl",
+				queries = "queries",
+			},
+			filetype = "simf",
+			tier = 0,
+		}
+	end,
+})
+
+vim.treesitter.language.register("simplicityhl", { "simf" })
+
+vim.api.nvim_create_autocmd("FileType", {
+	pattern = { "simf" },
+	callback = function()
+		vim.treesitter.start()
+	end,
+})
+```
+
+2. Restart Neovim and run:
+
+```vim
+:TSInstall simplicityhl
+```
+
+If everything is working correctly, you should see syntax highlighting in `.simf` files.
+
+**Note:** This method is compatible only with `nvim-treesitter` v0.10 or newer.
+