image.go:Modify the ref prescribing information

Signed-off-by: zhouhao <zhouhao@cn.fujitsu.com>

cmd/oci-create-runtime-bundle/oci-create-runtime-bundle.1.md

@@ -9,7 +9,7 @@ oci-create-runtime-bundle \- Create an OCI runtime bundle
 **oci-create-runtime-bundle** [--help|--version]
 
 # DESCRIPTION
-`oci-create-runtime-bundle` validates an application/vnd.oci.image.manifest.v1+json and unpacks its layered filesystem to `dest/rootfs`, although the target directory is configurable with `--rootfs`. See **oci-unpack**(1) for more details on this process.
+`oci-create-runtime-bundle` validates an application/vnd.oci.image.manifest.v1+json or an application/vnd.oci.image.manifest.list.v1+json and unpacks its layered filesystem to `dest/rootfs`, although the target directory is configurable with `--rootfs`. See **oci-unpack**(1) for more details on this process.
 
 Also translates the referenced config from application/vnd.oci.image.config.v1+json to a
 runtime-spec-compatible `dest/config.json`.
@@ -19,7 +19,7 @@ runtime-spec-compatible `dest/config.json`.
   Print usage statement
 
 **--ref**
-  The ref pointing to the manifest of the OCI image. This must be present in the "refs" subdirectory of the image. (default "v1.0")
+  The ref pointing to the manifest or manifest list of the OCI image. This must be present in the "refs" subdirectory of the image. (default "v1.0")
 
 **--rootfs**
   A directory representing the root filesystem of the container in the OCI runtime bundle. It is strongly recommended to keep the default value. (default "rootfs")

cmd/oci-image-validate/oci-image-validate.1.md

@@ -17,7 +17,7 @@ oci-image-validate \- Validate one or more image files
   Print usage statement
 
 **--ref** NAME
-  The reference to validate (should point to a manifest).
+  The reference to validate (should point to a manifest or a manifest list).
   Can be specified multiple times to validate multiple references.
   `NAME` must be present in the `refs` subdirectory of the image.
   Defaults to `v1.0`.

cmd/oci-unpack/oci-unpack.1.md

@@ -9,14 +9,14 @@ oci-unpack \- Unpack an image or image source layout
 **oci-unpack** [--help|--version]
 
 # DESCRIPTION
-`oci-unpack` validates an application/vnd.oci.image.manifest.v1+json and unpacks its layered filesystem to `dest`.
+`oci-unpack` validates an application/vnd.oci.image.manifest.v1+json or an application/vnd.oci.image.manifest.list.v1+json and unpacks its layered filesystem to `dest`.
 
 # OPTIONS
 **--help**
   Print usage statement
 
 **--ref**
-  The ref pointing to the manifest to be unpacked. This must be present in the "refs" subdirectory of the image. (default "v1.0")
+  The ref pointing to the manifest or manifest list to be unpacked. This must be present in the "refs" subdirectory of the image. (default "v1.0")
 
 **--type**
   Type of the file to unpack. If unset, oci-unpack will try to auto-detect the type. One of "imageLayout,image"