Check Plasma Scripting API Examples Are Valid

I think the first createActivity(...) example is incorrect. The API mentions the following:

• https://develop.kde.org/docs/plasma/scripting/api/
• https://invent.kde.org/plasma/plasma-workspace/blob/master/shell/scripting/scriptengine_v1.cpp#L223
• JSValue ScriptEngine::V1::createActivity(const QJSValue &nameParam, const QString &pluginParam)

There's likely a few other undocumented changes since:

• Plasma4 => Plasma5
• Port Plasma Desktop Scripting to QJSEngine
  plasma/plasma-workspace@033ad5ca

Misc:

[`createActivity(name, plugin)`](https://invent.kde.org/plasma/plasma-workspace/blob/master/shell/scripting/scriptengine_v1.cpp#L223)