Redeclaration in output go code

[jgoodall]

Description

This seems related to #8, but I dont need an enhancement in the xgen tool, just a way to solve the problem below.

I am having a similar problem when trying to use xgen on the Grobid xsd files: xgen -i ./grobid/grobid-home/schemas/xsd -o ./pkg/extraction/grobid -p grobid -l Go

It creates all the corresponding go files, albeit in a weird directory path (pkg/extraction/grobid/grobid/grobid-home/schemas/xsd/), but after moving the files to the expected path, the go compiler complains found packages schema (Grobid.xsd.go) and grobid (dcr.xsd.go). If I manually change the package from schema to grobid in Grobid.xsd.go I get a bunch of errors related to redeclared in this block. Is there any way to work around this issue?

Steps to reproduce the issue:

1. xgen -i ./grobid/grobid-home/schemas/xsd -o ./pkg/extraction/grobid -p grobid -l Go
2. mv pkg/extraction/grobid/grobid/grobid-home/schemas/xsd/* pkg/extraction/grobid && rm -rf pkg/extraction/grobid/grobid/grobid-home
3. Build:

pkg/extraction/extraction.go:25:2: found packages schema (Grobid.xsd.go) and grobid (dcr.xsd.go) in /Users/ojg/code/corpora/server/pkg/extraction/grobid```
5. Change package name to `grobid` in `Grobid.xsd.go` and build:
```go build -o bin/test .
pkg/extraction/grobid/tei.xsd.go:10:6: P redeclared in this block
	pkg/extraction/grobid/Grobid.xsd.go:2606:6: other declaration of P
pkg/extraction/grobid/tei.xsd.go:20:6: Hi redeclared in this block
	pkg/extraction/grobid/Grobid.xsd.go:2616:6: other declaration of Hi

Describe the results you received:

The code did not compile compile - see output above.

Describe the results you expected:

The code to compile.

Output of go version:

go version go1.22.1 darwin/arm64

xgen version or commit ID:

xgen version: 0.1.0

Environment details (OS, physical, etc.):

macOS 14.4 on MacBook Pro with M2.