crane/gcrane: add pages (#13853)

pages/common/crane-index-append.md

@@ -0,0 +1,30 @@
+# crane index append
+
+> Append manifest to a remote index.
+> This sub-command pushes an index based on an (optional) base index, with appended manifests.
+> The platform for appended manifests is inferred from the config file or omitted if that is infeasible.
+> More information: <https://github.com/google/go-containerregistry/blob/main/cmd/crane/doc/crane_index_append.md>.
+
+- Append manifest to a remote index:
+
+`crane index append`
+
+- Reference to manifests to append to the base index:
+
+`crane index append {{-m|--manifest}} {{manifest_name1 manifest_name2 ...}}`
+
+- Tag to apply to resulting image:
+
+`crane index append {{-t|--tag}} {{tag_name}}`
+
+- Empty base index will have Docker media types instead of OCI:
+
+`crane index append --docker-empty-base`
+
+- Append each of its children rather than the index itself (defaults true):
+
+`crane index append --flatten`
+
+- Display help:
+
+`crane index append {{-h|--help}}`