docs: fix stale GpuInfo::gfx_target intra-doc link (#22)

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: jorge-menjivar

src/lib.rs

@@ -623,7 +623,7 @@ pub fn cuda_host() -> Option<CudaHost> {
 ///
 /// `None` does not mean the GPU is unusable for compute: the kernel side is a
 /// separate component, and what a build has to target is
-/// [`GpuInfo::gfx_target`], reported with no `ROCm` installed at all.
+/// [`GpuInfo::arch_target`], reported with no `ROCm` installed at all.
 ///
 /// ```no_run
 /// use gpu_probe::RocmVersion;