Default .gd script naming should follow convention

[ivanskodje]

Describe the project you are working on

Any Godot Engine project.

Describe the problem or limitation you are having in your project

When I attempt to attach a new script to a Node, the script name defaults to the node name that uses PascalCase. (Steam's Godot Engine version as of 2021-03-29)

For Example:

1. Create a MyNode node.
2. Attach a new script.
3. Notice the default name is "MyNode.gd" instead of "my_node.gd" which would be the Godot Engine's documented naming convention.

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

Instead of creating default gdscript file name using PascalCase, it should be converted to snake_case by default, so we won't have to manually change the name in order to follow GDscript naming conventions

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

In the Godot Engine source code, parse the Node name into snake_case before populating the GDScript file name's text box.

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

No. The only way to "fix" this is to break coding conventions and use snake_case for Node names as well.

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

Because we both follow and encourage others to follow the standard conventions, without having to make them think and manually "correct" it. :)

[YuriSizov]

Duplicate of #1211