fix duplicate labels in api_break.dox

Author: jef-n

doc/api_break.dox

@@ -1251,12 +1251,6 @@ QgsLayerTreeLayer        {#qgis_api_break_3_0_QgsLayerTreeLayer}
 - setVisible() is replaced by QgsLayerTreeNode::setItemVisibilityChecked()
 - readXml() does not resolve layer from the layer ID anymore. Call resolveReferences() or use readXml() override with QgsProject as the second argument.
 
-QgsLayerTreeNode        {#qgis_api_break_3_0_QgsLayerTreeNode}
-----------------
-
-- readXml() does not resolve layers from the layer IDs anymore. Call resolveReferences() or use readXml() override with QgsProject as the second argument.
-
-
 QgsLayerTreeMapCanvasBridge        {#qgis_api_break_3_0_QgsLayerTreeMapCanvasBridge}
 -----------------
 
@@ -1288,6 +1282,7 @@ QgsLayerTreeNode        {#qgis_api_break_3_0_QgsLayerTreeNode}
 - readCommonXML() has been renamed to readCommonXml()
 - writeCommonXML() has been renamed to writeCommonXml()
 - the signature of the visibilityChanged() signal is changed to visibilityChanged( QgsLayerTreeNode *node )
+- readXml() does not resolve layers from the layer IDs anymore. Call resolveReferences() or use readXml() override with QgsProject as the second argument.
 
 QgsLimitedRandomColorRampDialog        {#qgis_api_break_3_0_QgsLimitedRandomRampDialog}
 -------------------------------
@@ -1623,7 +1618,7 @@ QgsRasterCalcNode        {#qgis_api_break_3_0_QgsRasterCalcNode}
 - QgsRasterCalcNode::calculate has been removed, use method with QgsRasterBlocks instead.
 
 
-QgsRasterCalculator     {#qgis_api_break_3_0_QgsRasterCalcNode}
+QgsRasterCalculator     {#qgis_api_break_3_0_QgsRasterCalculator}
 -------------------
 
 - Cancelled (Result enum value) has been renamed to Canceled  <!--#spellok-->