Rename `showResizeFeedback` and `eraseResizeFeedback` in AbsoluteBasedLayoutEditPolicy

[ptziegler]

They should be called showSourceFeedback and eraseSourceFeedback to match the GEF API. We need to explicitly check whether the request type is AbsoluteBasedSelectionEditPolicy.REQ_RESIZE. This then also makes the workaround in the AbsoluteBasedSelectionEditPolicy obsolete.

windowbuilder/org.eclipse.wb.core/src/org/eclipse/wb/internal/core/gef/policy/layout/absolute/AbsoluteBasedSelectionEditPolicy.java

Lines 75 to 87 in 98b82d1

	@Override
	protected void showSourceFeedback() {
	getLayoutEditPolicy().showResizeFeedback(getSourceRequest());
	setShowingFeedback(true);
	}
	@Override
	protected void eraseSourceFeedback() {
	if (isShowingFeedback()) {
	setShowingFeedback(false);
	getLayoutEditPolicy().eraseResizeFeedback(getSourceRequest());
	}
	}