Change CanvasItem's update() to _update() for consistency

[SilencedPerson]

Describe the project you are working on

a game

Describe the problem or limitation you are having in your project

i want to name function update but that requires me to overwrite the drawing update method

Describe the feature / enhancement and how it helps to overcome the problem or limitation

I will now be able to define custom update() function

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

the name is changed to _update() to be consistent with the rest of the method names across the engine.

If this enhancement will not be used often, can it be worked around with a few lines of script?

gdscript is core.

Is there a reason why this should be core and not an add-on in the asset library?

it cannot be done with a add-on

[Zireael07]

Why close?

[KoBeWi]

Something similar was suggested here: godotengine/godot#54161 (comment)
Leading underscore is reserved for virtual methods, so it couldn't be renamed to _update() anyways.

[SilencedPerson]

Why close?

sorry for late reply, it was for the reason KoBeWi mentioned.