Shader error messages

[wipfli]

I was editing some shaders yesterday and of course made some typos and bugs. To my surprise, there were no error messages displayed in the chrome browser console. Also the syntax highlighting in vscode did not show any errors in the .glsl files.

Is there a way to get some error messages/debug info when writing shaders?

[HarelM]

Might be related to this PR:

• Inform better if shaders doesn't compile #2655

I'm not very familiar with this part.
cc: @birkskyum.