[no sq] Misc fixes

[sfan5]

commit 1: 🤷‍♂️
commit 2: fixes #15658
commit 3: fixes #15652
commit 4: fixes #15584

To do

This PR is Ready for Review.

How to test

maybe ask ChatGPT, idk

[HybridDog]

maybe ask ChatGPT, idk

I think Microsoft would have more elation if we ask the Copilot. I have done this and am very unsatisfied with the result:

How to test the changes proposed in PR #15661:

1. Review the Pull Request Description:

   • The description mentions "maybe ask ChatGPT, idk" indicating there are no specific testing instructions provided by the author.

2. Review the Changed Files:

   • The PR changes 17 files including doc/lua_api.md, irr/include/SMaterial.h, irr/include/SMaterialLayer.h, and several files in the src/client and src/content directories.
   • You can view the list of changed files here.

3. Clone the Repository and Checkout the PR Branch:

   git clone https://github.com/minetest/minetest.git
   cd minetest
   git fetch origin pull/15661/head:pr-15661
   git checkout pr-15661

4. Build and Test the Project:

   • Follow the project's build and test instructions, typically found in the README.md or CONTRIBUTING.md files.
   • Ensure you thoroughly test the areas affected by the changes.

If you have further questions or need additional guidance, feel free to ask!

[SmallJoker]

Tested the error handling with the code provided in #15652, modified to do 60 steps.

you cant see me after 60 steps
58	0.017416000366211
you cant see me after 60 steps
59	0.016967000439763
you cant see me after 60 steps
60	0.018226999789476
you cant see me after 60 steps
61	0.016819000244141

Works.

The other changes look good. Please assume 👍 after the minor comments are handled.