Description

This PR fixes a bug that occurs if you pass rename --column and empty list like ls | rename -c [].

Before

> ls | rename -c []
thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', crates\nu-command\src\filters\rename.rs:110:15
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

After

> ls | rename -c []
Error: nu::shell::type_mismatch (link)

  × Type mismatch.
   ╭─[entry #1:1:1]
 1 │ ls | rename -c []
   ·                ─┬
   ·                 ╰── The list cannot be empty and must contain only two values: the column's name and its replacement value
   ╰────

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

After Submitting

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