crane/gcrane: add pages (#13853)

pages/common/crane-digest.md

@@ -0,0 +1,20 @@
+# crane digest
+
+> Get the digest of an image.
+> More information: <https://github.com/google/go-containerregistry/blob/main/cmd/crane/doc/crane_digest.md>.
+
+- Get the digest of an image:
+
+`crane digest {{image_name}}`
+
+- Print the full image reference by digest:
+
+`crane digest {{image_name}} --full-ref`
+
+- Specify path to tarball containing the image:
+
+`crane digest {{image_name}} --tarball {{path/to/tarball}}`
+
+- Display help:
+
+`crane digest {{-h|--help}}`