Fix file names

Signed-off-by: Steve Lasker <[email protected]>

Author: SteveLasker

artifact-spec.md renamed to artifact-manifest-spec.md

@@ -101,7 +101,7 @@ A signature, or an SBoM, would be persisted with the content persisted in the `[
 
 ![Notary v2 signature](./media/notaryv2-signature.svg)
 
-**A Notary v2 signature of the `net-monitor:v1` image:**
+**An Artifact Manifest, capturing the Notary v2 signature of the `net-monitor:v1` image:**
 
 - **repository**: `net-monitor`
 - **digest**: `sha256:8ac803930ea3ba1e54bc25c2bdc53edd0284c62ed651fe7b00369da519a3c222`
@@ -131,7 +131,7 @@ A signature, or an SBoM, would be persisted with the content persisted in the `[
 
 The same `net-monitor:v1` image may have an associated SBoM. The SBoM content would be persisted as one or more `[blobs]` with a `subjectManifest` referencing the `net-monitor:v1` image (by digest).
 
-![Notary v2 signature](./media/net-monitor-sbom.svg)
+![Sample SBOM](./media/net-monitor-sbom.svg)
 
 - **repository**: `net-monitor`
 - **digest**: `sha256:7a781a3930ea3ba1e54bc25c2bdc53edd0284c62ed651fe7b00369da519a3c1a`
@@ -375,7 +375,7 @@ oci-reg delete registry.acme-rockets.io/net-monitor@sha256:b5b2b2c507a0944348e03
 [lifecycle-management]:               ./artifact-reftype-spec.md#lifecycle-management
 [oci-image-manifest-spec]:            https://github.com/opencontainers/image-spec/blob/master/manifest.md
 [oci-artifacts]:                      https://github.com/opencontainers/artifacts
-[oci-artifact-manifest-spec]:         ./artifact-spec.md
+[oci-artifact-manifest-spec]:         ./artifact-manifest-spec.md
 [oci-image-index]:                    https://github.com/opencontainers/image-spec/blob/master/image-index.md
 [oci-distribution-spec]:              https://github.com/opencontainers/distribution-spec
 [referrers-api]:                      ./manifest-referrers-api.md