# Description
This PR closes#14137 and allows the display hook to be set on byte
streams. So, with a hook like this below.
```nushell
display_output: {
metadata access {|meta| match $meta.content_type? {
"application/x-nuscript" | "application/x-nuon" | "text/x-nushell" => { nu-highlight },
"application/json" => { ^bat --language=json --color=always --style=plain --paging=never },
_ => {},
}
} | table
}
```
You could type `open toolkit.nu` and the text of toolkit.nu would be
highlighted by nu-highlight. This PR also changes the way content-type
is assigned with `open`. Previously it would only assign it if `--raw`
was specified.
Lastly, it changes the `is_external()` function to only say
`ByteStreamSource::Child`'s are external instead of both Child and
`ByteStreamSource::File`. Again, this was to allow the hook to function
properly. I'm not sure what negative ramifications changing
`is_external()` could have, but there may be some?
# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->
# Tests + Formatting
<!--
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used` to
check that you're using the standard code style
- `cargo test --workspace` to check that all tests pass (on Windows make
sure to [enable developer
mode](https://learn.microsoft.com/en-us/windows/apps/get-started/developer-mode-features-and-debugging))
- `cargo run -- -c "use toolkit.nu; toolkit test stdlib"` to run the
tests for the standard library
> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```
-->
# After Submitting
<!-- If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
-->
af9c31152a