fix(doc): Make private types which show up in the rustdocs public (#13230)

`CrossIsolateStore`, `ExtensionBuilder` and `InMemoryChannelResource`
are private types which are referred to by other public APIs, and so
don't show up as links in the rustdoc. This is especially confusing for
`ExtensionBuilder`, since there is nothing in the docs that explains how
to build an extension.

Exposing these three types doesn't add any new capabilities:
`ExtensionBuilder` can be created from `Extension::builder()`,
`SharedArrayBufferStore` and `CompiledWasmModuleStore` already enable
doing anything that `CrossIsolateStore` can do by itself, and
`InMemoryChannelResource` isn't constructable.

0 files changed, 0 insertions, 0 deletions