Issue for collecting API doc fixes for OpenJFX19:

1. Typo in TextFormatter class docs: intial -> initial
2. javafx/concurrent/package.html: "javafx.task" -> "javafx.concurrent"
3. https://openjfx.io/javadoc/18/javafx.graphics/javafx/concurrent/Service.html: "Service which read -> "Service that reads"
4. https://openjfx.io/javadoc/18/javafx.graphics/javafx/concurrent/ScheduledService.html: "an backoff" -> "a backoff"
5. ObservableSetWrapper#retainAll: "Keeps only elements that are included the specified collection" -> missing "in"
6. https://openjfx.io/javadoc/18/javafx.base/javafx/beans/binding/ObjectBinding.html#onInvalidating(): weird phrasing, needs a soft rewrite
7. Property.java L103: "property1.bindBirectional(property2)" -> "property1.bindBidirectional(property2)"