Fix copy-pasting mistake in extended material bindless example

[janhohenheim]

Objective

• The docs are a bit weird, which is probably due to someone at some point accidentally copy-pasting the wgsl correspondence code

Solution

• Write the actual code
• Also use our fancy #{MATERIAL_BIND_GROUP} in the docs, given that it's used in the shader :)
• Split the line a liiiiittle bit differently

Testing

• None, just docs. Well, I did make sure that the stuff in the docs is the same as in the shader!

[janhohenheim]

Feel free to move it out of the milestone, I just put it there because having fixed docs would be neat.

[pcwalton]

Yeah, looks correct, sorry for the mistake there!

[janhohenheim]

@pcwalton thank you so much for making this example in the first place, it was exactly what I needed and I think I would not have been able to piece it together on my own if it didn't exist :D

[NicoZweifel]

Nice catch! I think having good docs would be really clutch for bindless, it took me days to figure out quirks with bindless.