x/tools/cmd/goyacc: goyacc does not support `%code`

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

What did you do?

$ curl -o parser_yacc.y https://gitlab.apertis.org/pkg/apparmor/-/raw/ubuntu/master/parser/parser_yacc.y
$ goyacc -o output parser_yacc.y
invalid escape, or illegal reserved word: code: parser_yacc.y:182

What did you expect to see?

Successful processing of parser_yacc.y.

What did you see instead?

invalid escape, or illegal reserved word: code: parser_yacc.y:182