Bug 189636 Custom rule template failing
Null poonter exception being thrown when trying to add a custom rule which is causing the rule cretion to fail. Also there is a minor typo in the rule template string.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
* @see org.eclipse.ui.navigator.INavigatorContentService#getSaveableService()
	 */
	public INavigatorSaveablesService getSaveablesService() {
		synchronized (this) {
			if (navigatorSaveablesService == null) {
				navigatorSaveablesService = new NavigatorSaveablesService(this);
				assistant.addListener(navigatorSaveablesService);
			}
			return navigatorSaveablesService;
		}
	}
	
	/** 
	 * Not API as of 3.3. 
	 * @return The extension state service for this content service. 
	 * 
	 */
	public NavigatorExtensionStateService getExtensionStateService() {
		if (navigatorExtensionStateService == null) {
			navigatorExtensionStateService = new NavigatorExtensionStateService(this);
		}
		return navigatorExtensionStateService;
	}
	
	/**
	 * Non-API method to return a shell.
	 * @return A shell associated with the current viewer (if any) or <b>null</b>.
	 */
	public Shell getShell() {
		if(structuredViewerManager != null && structuredViewerManager.getViewer() != null) {