Where is the source code used in the examples, please?

### What I found/tried:
I am new to AssertJ. I'm reading https://joel-costigliola.github.io/assertj/assertj-swing-input.html

There's a few lines of code pointing me in a good direction. They assume I already know how to import everything needed. The one minute quick-start doesn't have a runable demo.

I looked in various sub-folders for examples with no luck.

### What I expect:
A working example I can run locally to see these things in action for myself? Same way a "how to use [swing feature x]" would have run-able source code. Example, [JButton](https://docs.oracle.com/javase/tutorial/uiswing/components/button.html) links to [this demo](https://docs.oracle.com/javase/tutorial/displayCode.html?code=https://docs.oracle.com/javase/tutorial/uiswing/examples/components/ButtonDemoProject/src/components/ButtonDemo.java).

### separately:
the quick-start code assumes I know the title of my frame. As my app is multilingual I can't be sure what translation is running or the name of the frame around the panel I want to test. Can application.start() return the root frame?

AssertJ Swing の入力ガイドと 1 分間のクイックスタートから始め、その後、文書化されている application.start() のフローがどのように使用されているかを調べます。実行可能な例を追加できるかどうかを判断し、root frame を返すという要望を別途評価します。完了条件には、実行可能な例と、明確に文書化された API の動作を含める必要があります。

索引モデルが issue の本文から書いたものです。