Add option to allow for a generated code comment

[adayNU]

We'd like for GH / Reviewable to understand these files are generated. Would you be open to adding a flag like: --ts_proto_opt=header=true

Which would prepend something like // Code generated by protoc-gen-ts. DO NOT EDIT. to the first line of every file.

If this seems reasonable, I'd be happy to implement.

[stephenh]

@adayNU yep, that sounds like a good idea; a PR would be great!

[boukeversteegh]

It could even be there by default. It's a comment so it will be stripped in most cases by webpack anyway.

[stephenh]

Yep, good point / +1 to a hard-coded value. We could someday have like a prefixFile=./my-custom-prefix.txt opt to override it, but I assume for now we could drop basically any known string into prefixDisableLinter and be good enough.

[dasco144]

I think this might be a nice feature to add. We could include additional information, like how the protoc-gen-go plugin does

// Code generated by protoc-gen-go. DO NOT EDIT.
// versions:
// 	protoc-gen-go v1.29.0
// 	protoc        v4.22.2
// source: foo.proto

[stephenh]

Better late than never :-) thank you @dasco144 ! 🎉