Fix and update docs and examples for slang modules

[swoods-nv]

No description provided.

[cheneym2]

@swoods-nv Do you have any specific documentation that is known to be lacking or incorrect?

https://shader-slang.org/slang/user-guide/modules.html is documentation about modules in general, and there are numerous examples of module use. Not aware of anything that needs an overhaul.

Is this issue still valid, and if so, could you provide some more guidance on what needs update?

[cheneym2]

I see at least one stale note in the modules.html documentation. Pretty sure I can remove this.

Note

Future versions of the Slang system will support loading of modules from pre-compiled binaries instead of source code. The same import keyword will continue to work in that case.