docs: Copilot improvements

[MarcinVaadin]

Fixes #1573

[jouni]

What does and more refer to? This isn't a marketing page, where we should build up “hype”. Stick to what we know our products do and don't do, and don't leave readers guessing. Also, avoid getting excited in documentation (avoid exclamation marks).

I don't fully understand what improves saving changes you made into your files means. What does “saving changes you made into your files” mean more concretely, and how does Copilot improve that?

Suggested change

	To get the best Copilot experience use the Vaadin plugin for link:https://plugins.jetbrains.com/plugin/23758-vaadin[IntelliJ] or link:https://marketplace.visualstudio.com/items?itemName=vaadin.vaadin-vscode[Visual Studio Code]. It improves saving changes you made into your files, enables seamless Undo integration (IntelliJ only) and more!
	To get the best Copilot experience, use the Vaadin plugin for link:https://plugins.jetbrains.com/plugin/23758-vaadin[IntelliJ] or link:https://marketplace.visualstudio.com/items?itemName=vaadin.vaadin-vscode[Visual Studio Code]. The plugin improves saving changes you made into your files and integrates with the undo-functionality (IntelliJ only).

[MarcinVaadin]

improves saving changes you made into your files

It was suppose to mean that if you use plugin, IDE document is automatically refreshed. Without it user must rely on IDE's file system watcher and sometimes changes might be unnoticed.

[jouni]

Right, so when I edit a view with Copilot, the plugin makes sure the source code file, if opened in the IDE, shows the updated code as well. I think we should explain it like that instead.

[MarcinVaadin]

Yes, exactly

[russelljtdyer]

Looks good.