[Migrated] Minor Bug: Misleading error message when compile succeeds but no *.spv was found

Issue automatically imported from old repo: https://github.com/EmbarkStudios/rust-gpu/issues/955
Old labels: t: enhancement
Originally creatd by Firestar99 on 2022-11-30T14:32:49Z

If you compile a crate with rust-gpu but forget to add

[lib]
crate-type = ["lib", "dylib"]

in it's cargo.toml rust-gpu will error out with: Artifact created when compilation succeeded.
This Error is outright wrong: What actually happened is that compilation succeeded but NO *.spv artifact was found.

The error is thrown in crates/spirv-builder/src/lib.rs line 538, at the end of the invoke_rustc() method.
I'd like to suggest replacing this message with Compilation succeeded but no .spv Artifact was created! Make sure the crate-type includes \"dylib\".

crates/spirv-builder/src/lib.rsを開き、invoke_rustc()の末尾にある538行目を確認します。コンパイルが成功した後にアーティファクトなしのケースに至る経緯を確認します。エラーメッセージが .spv アーティファクトが作成されなかったことを正確に説明し、必要な crate-type 設定を示していれば完了です。