Bug 250604 [FieldAssist] API - ContentProposalAdapter needs isShowing() method
Please implement a method ContentProposalAdapter.isShwoing(). The method should return a boolean whether the content assistant proposal popup is open or not.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
if (p != null) {
				showProposalDescription();
			}
			return value;
		}
		/**
		 * Closes this popup. This method is extended to remove the control
		 * listener.
		 * 
		 * @return <code>true</code> if the window is (or was already) closed,
		 *         and <code>false</code> if it is still open
		 */
		public boolean close() {
			popupCloser.removeListeners();
			if (infoPopup != null) {
				infoPopup.close();
			}
			boolean ret = super.close();
			notifyPopupClosed();
			return ret;
		}
		/*
		 * Show the currently selected proposal's description in a secondary
		 * popup.
		 */
		private void showProposalDescription() {
			
			
			if (!pendingDescriptionUpdate) {