Add changed return values to api break

doc/api_break.dox

@@ -2615,6 +2615,10 @@ displayExpression instead. For the map tip use mapTipTemplate() instead.
 - setLayerTransparency, layerTransparency, and layerTransparencyChanged were removed. Use opacity, setOpacity and opacityChanged instead.
 - The c++ signature for uniqueValues() has changed (the PyQGIS method remains unchanged)
 - hasGeometryType() has been removed, replaced by QgsMapLayer::isSpatial()
+- addRing() now returns QgsGeometry::OperationResult enum, integer representation of returned values may have changed
+- addPart() now returns QgsGeometry::OperationResult enum, integer representation of returned values may have changed
+- splitParts() now returns QgsGeometry::OperationResult enum, integer representation of returned values may have changed
+- splitFeatured() now returns QgsGeometry::OperationResult enum, integer representation of returned values may have changed
 
 
 QgsVectorLayerEditBuffer        {#qgis_api_break_3_0_QgsVectorLayerEditBuffer}