_fnOnNavigatable = () => {
				const oTypeahead = this.getTypeahead(); // as might already be destroyed and removed
				return oTypeahead?.navigate(iStep);
			}
Triggers navigation in the value help.

<b>Note:</b> This function must only be called by the control the <code>ValueHelp</code> element
belongs to, not by the application.

@param {int} iStep Number of steps for navigation (e.g. 1 means next item, -1 means previous item)

@private
@ui5-restricted sap.ui.mdc.field.FieldBase