feat(gen): Output when generating is succeeded (#55)

The message makes it easy to notify it's completed.

src/main.ts

@@ -1,5 +1,5 @@
 import { parseArgs } from "parse_args";
-import { resolve } from "path";
+import { basename, resolve } from "path";
 import { readTOML, writeXML } from "./libs/mod.ts";
 import { Lists } from "./types/mod.ts";
 
@@ -20,3 +20,4 @@ try {
  console.error(`🚨 ${error.message}`);
  Deno.exit(1);
 }
+console.log(`✅ ${basename(flags.feeds)}`);