add annotation generator: neogen

after/plugin/neogen.lua

@@ -0,0 +1,10 @@
+local status_ok, neogen = pcall(require, "neogen")
+if not status_ok then
+	return
+end
+
+neogen.setup {
+  enabled = true,
+  input_after_comment = true,
+  snippet_engine = "luasnip",
+}