There's no such symbol as expand_template_rule in @aspect_bazel_lib//lib:expand_template.bzl

The code in https://github.com/bazel-contrib/rules_oci/blob/main/docs/push.md#examples is incorrect.
It says we have to load:
```
load("@aspect_bazel_lib//lib:expand_template.bzl", "expand_template_rule")
```
But then we use a function that's not loaded:
```
expand_template(
name = "stamped",
out = "_stamped.tags.txt",
template = ["0.0.0"],
stamp_substitutions = {"0.0.0": "{{BUILD_EMBED_LABEL}}"},
)
```

Open docs/push.md at the examples section and compare the loaded symbol with the function used in the snippet. Update the example so its load and invocation agree, then verify it no longer references the unavailable symbol.

Written by the indexing model from the issue text.