Improvements to gdscript documentation comments page

[mgrider]

This is in regards to "documentation comments", which are located here: https://docs.godotengine.org/en/stable/tutorials/scripting/gdscript/gdscript_documentation_comments.html I have some suggestions for improving that page, which I think are timely given the improvements in 4.4 related to inline documentation.

1. I think this page should make it clearer that the placement of "script documentation" can go above or below the definition of the script. The only example on the page is below the extends keyword, which is inconsistent with documentation of "script member documentation" (which are always placed above the definition of the member). The "above" placement is both less ambiguous, and more consistent with other language placements for similar-use comments (including C#), and so I think it should be preferred. It's worth noting that both placements (above and below) do already work.

I would recommend changing the paragraph immediately below the "Documenting a script" header to add a sentence about this:

Comments documenting a script must come before any member documentation. They can appear above or below the class_name and extends keywords. A suggested format for script documentation can be divided into three parts.

2. This is the current example from that section's documentation:

extends Node2D
## A brief description of the class's role and functionality.
##
## The description of the script, what it can do,
## and any further detail.
##
## @tutorial:             https://example.com/tutorial_1
## @tutorial(Tutorial 2): https://example.com/tutorial_2
## @experimental

I propose that we change the example to above the definition, and add the class_name as well. Here is one possibility:

## A brief description of the ScriptExample class's role and functionality.
##
## The description of the script, what it can do,
## and any further detail.
##
## @tutorial:             https://example.com/tutorial_1
## @tutorial(Tutorial 2): https://example.com/tutorial_2
## @experimental
class_name ScriptExample extends Node2D

3. Along the same lines as the 2nd recommendation, I would also propose to change the "Complete script example" further down the page in a manor similar to the above recommendations.

4. Finally, my last recommendation is a bit more nebulous, and I welcome discussion, but I think it would be nice to include some examples of how these comments appear in the Godot text editor. Where these should appear, and how many, is up for debate.

[dalexeev]

The script's or outer class's doc comment is below the header for historical reasons. Also, there's a small conceptual problem with the fact that @tool and @static_unload are script annotations, not the outer class annotations. Plus there are standalone @warning_ignore_{start,restore} annotations. And both class_name and extends are optional.

Yes, we should mention that both options are supported, and the user can choose either. But I'm not sure if we should change the examples and the officially recommended order of script elements.