editorial: Reorder attributes in GPUPipelineError interface - #6265

Previews, as seen when this build job started (9f13850):
WebGPU _{webgpu.idl | Explainer | Correspondence Reference}
WGSL _{grammar.js | wgsl.lalr.txt}

sagudev marked as non substantive for IPR from ash-nazg.

This is not alphabetical, so maybe we should revere this and change all others to be alphabetically ordered.

I would reverse it because most things are
[Exposed=(Window, Worker), SecureContext] so it makes sense for Serializable things to be
[Exposed=(Window, Worker), SecureContext, Serializable].

There's only 3 Serializable things anyway.