Update documentation

cura/Settings/ContainerManager.py

@@ -235,7 +235,7 @@ class ContainerManager(QObject):
 
         return True
 
-    ##  Set a metadata entry of the specified container.
+    ##  Set a setting property value of the specified container.
     #
     #   This will set the specified property of the specified setting of the container
     #   and all containers that share the same base_file (if any). The latter only

resources/qml/Preferences/MaterialView.qml

@@ -166,6 +166,8 @@ TabView
 
                     onEditingFinished:
                     {
+                        // This does not use a SettingPropertyProvider, because we need to make the change to all containers
+                        // which derive from the same base_file
                         Cura.ContainerManager.setContainerProperty(base.containerId, "material_diameter", "value", value)
                         base.setMetaDataEntry("properties/diameter", properties.diameter, value)
                     }