Do not reformat generated files

[markuspeloquin]

I use code generation as well as goimports (actually the gosimports fork). Unfortunately, any generated files also need to be reformatted or it causes churn on commits. It would probably be good if there were commit hooks to check formatting automatically, but I also use golangci-lint --fix, which is slow, and then you have to worry about commiting the changes. It'd be better if generated files were just left alone.

What version of Go are you using (go version)? 1.20.4
What operating system and processor architecture are you using? linux, amd64
What did you do? go generate ./... && git commit -a && goimports -w .
What did you expect to see? I expected nothing to be reformatted
What did you see instead? Generated files are reformatted

https://pkg.go.dev/cmd/go#hdr-Generate_Go_files_by_processing_source

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