Consider edge case specification testing through code compilation

[Failure in code generation if nested attribute defines name with reserved Go keyword](https://github.com/hashicorp/terraform-plugin-codegen-framework/issues/76#top) describes a bug in which usage of reserved Go keywords (e.g., `type`), when used as attribute names in nested attributes results in code generation failure.

It is worth adding specifications that test such edge cases by, for example, using reserved Go keywords as attribute names in nested attributes, and testing that the generated code compiles.

### References

- https://github.com/hashicorp/terraform-plugin-codegen-framework/pull/77#pullrequestreview-1694867025