docs: Add testing with neovim instructions (#1)

README.md

@@ -1,2 +1,22 @@
 # protols
 Language server for proto files
+
+## Testing with neovim
+```lua
+local client = vim.lsp.start_client({
+	name = "protols",
+	cmd = { "<absolute path to protols binary>" },
+})
+
+if not client then
+	vim.notify("Could not connect to protols server")
+end
+
+vim.api.nvim_create_autocmd("FileType", {
+	pattern = "proto",
+	callback = function()
+		vim.lsp.buf_attach_client(0, client)
+	end,
+})
+
+```