fix: error raised if buffer id is invalid

Author: pipoprods

lua/range-highlight/init.lua

@@ -157,7 +157,9 @@ function M.setup(opts)
 	vim.api.nvim_create_autocmd({ "CmdlineChanged" }, {
 		pattern = "*",
 		callback = debounce(M.opts.debounce.wait, function(ev)
-			vim.api.nvim_buf_clear_namespace(ev.buf, ns_id, 0, -1)
+			if vim.api.nvim_buf_is_valid(ev.buf) then
+				vim.api.nvim_buf_clear_namespace(ev.buf, ns_id, 0, -1)
+			end
 
 			local cmdline = vim.fn.getcmdline()
 			---@type integer|nil