Event handling doesn't support AnnouncementSet

[tinchodias]

Reproduce with:

BlElement new
    addEventHandlerOn: BlClickEvent, BlMouseDownEvent, BlMouseUpEvent
    do: [ ].

to get a "Instance of AnnouncementSet did not understand #enableIn:"

In Pharo12.

[tinchodias]

For the record, I did a first try and failed to fix it. I share the code below.

I created this test in BlEventTest:

testAnnouncementSet

    | element events |
    events := OrderedCollection new.

    element := BlElement new.
    element
        addEventHandlerOn: BlClickEvent, BlMouseMoveEvent
        do: [ :anEvent | events add: anEvent class ].

    BlSpace
        simulateMouseMoveInside: element;
        simulateClickOn: element button: BlMouseButton primary;
        simulateMouseDownOn: element; "should be ignored"
        simulateClickOn: element button: BlMouseButton secondary.

    self assert: events asArray equals: { BlMouseMoveEvent. BlClickEvent. BlClickEvent }

and created this extension in AnnouncementSet:

enableIn: aBlElementEventDispatcher

    ^ self do: [ :each | each enableIn: aBlElementEventDispatcher ]