Rename setSelectionExtruder to setExtruderForSelection

This matches more closely with the naming of the other selection
actions.

cura/CuraActions.py

@@ -75,8 +75,11 @@ class CuraActions(QObject):
                     op.addOperation(RemoveSceneNodeOperation(group_node))
         op.push()
 
+    ##  Set the extruder that should be used to print the selection.
+    #
+    #   \param extruder_id The ID of the extruder stack to use for the selected objects.
     @pyqtSlot(str)
-    def setSelectionExtruder(self, extruder_id: str) -> None:
+    def setExtruderForSelection(self, extruder_id: str) -> None:
         operation = GroupedOperation()
         for node in Selection.getAllSelectedObjects():
             if node.callDecoration("getActiveExtruder") == extruder_id:

resources/qml/Menus/ContextMenu.qml

@@ -32,7 +32,7 @@ Menu
             enabled: UM.Selection.hasSelection
             checkable: true
             checked: ExtruderManager.selectedObjectExtruders.indexOf(model.id) != -1
-            onTriggered: CuraActions.setSelectionExtruder(model.id)
+            onTriggered: CuraActions.setExtruderForSelection(model.id)
             shortcut: "Ctrl+" + (model.index + 1)
         }
         onObjectAdded: base.insertItem(base.findItemIndex(extruderHeader) + index, object)