change include dirs separator to colon (#8873)

# Description
This PR changes the include_path separator from a semicolon to a colon.
It seems that semicolon is not parsed well as an argument to nushell.

# 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 -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-std/tests/run.nu` 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.
-->

src/main.rs

@@ -141,7 +141,7 @@ fn main() -> Result<()> {
         let span = include_path.span;
         let vals: Vec<_> = include_path
             .item
-            .split(';')
+            .split(':')
             .map(|x| Value::String {
                 val: x.trim().to_string(),
                 span,