Remove cd w/ abbreviations (#10588)

# Description

This removes the old style "cd with abbreviations" that would attempt to
guess what directory you wanted to `cd` to. This would sometimes have
false positives, so we left it off by default in the config.

In the current main, we have much-improved path completions
(https://github.com/nushell/nushell/pull/10543) so you can now do `cd
a/b<tab>` and get a much better experience (because you can see the
directory you're about to cd to). This removes the need for the previous
abbreviation system.

# User-Facing Changes

This does remove the old abbreviation system. It will likely mean that
old config files that have settings for abbreviations will now get
errors.

update: here's an example of the error you'll see:


![image](https://github.com/nushell/nushell/assets/547158/6847a25d-895a-4b92-8251-278a57e8d29a)

# 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 std testing; testing run-tests --path
crates/nu-std"` 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.
-->

crates/nu-utils/src/sample_config/default_config.nu

@@ -150,10 +150,6 @@ $env.config = {
         always_trash: false # always act as if -t was given. Can be overridden with -p
     }
 
-    cd: {
-        abbreviations: false # allows `cd s/o/f` to expand to `cd some/other/folder`
-    }
-
     table: {
         mode: rounded # basic, compact, compact_double, light, thin, with_love, rounded, reinforced, heavy, none, other
         index_mode: always # "always" show indexes, "never" show indexes, "auto" = show indexes when a table has "index" column