[Feature] The list type in config does append

[BayMaxBHL]

What is the feature?

The config file is really nice in python format, making the config file easy to view.
I also use multiple config merges frequently.
The experiment-config often needs to include datasets-config, schedules-config, and default-runtime-config.
If it is a dictionary-type setting, there is an official tutorial to modify or supplement the specified part.

However, if it is a List, you can only override the setting if you want to supplement it. Totally defeats the purpose of List.
Some common Settings can cause problems with lists.
For example, visualizer vis_backends. Maybe I need to fix TensorboardVisBackend for debugging, and then use WandbVisBackend.
For example, hooks, the official tutorial recommends that customizations be placed in custom_hooks (I later discovered that customizations can also be placed in default_hooks to solve this problem), and different hooks distributed in multiple config cannot be merged into one custom_hooks.

Any other context?

No response