TextEditorComponent - when updated synchronously, update even when hidden

[maxbrunsfeld]

Atom's TextEditor objects normally update their DOM element asynchronously for performance reasons. They also use an IntersectionObserver to avoid unnecessary updates while they are not visible.

There is currently a setUpdatedSynchronously method that you can use to force text editors to always update immediately. Previously, even when editors were configured to update synchronously, they would not update unless visible. This PR causes text editors which have been set to update synchronously to update their DOM immediately even when hidden. I think that this is the behavior most users would want from the setUpdatedSynchronously method; it's typically a method that you call on a text editor when you need to interact with its DOM element programmatically and you don't want to the normal optimizations that prevent updates.

[maxbrunsfeld]

This turned out not to be necessary.