Use variable names directly in the format strings (#7906)

# Description

Lint: `clippy::uninlined_format_args`

More readable in most situations.
(May be slightly confusing for modifier format strings
https://doc.rust-lang.org/std/fmt/index.html#formatting-parameters)

Alternative to #7865

# User-Facing Changes

None intended

# Tests + Formatting

(Ran `cargo +stable clippy --fix --workspace -- -A clippy::all -D
clippy::uninlined_format_args` to achieve this. Depends on Rust `1.67`)

crates/nu-command/tests/commands/zip.rs

@@ -19,7 +19,7 @@ fn zips_two_tables() {
     Playground::setup("zip_test_1", |dirs, nu| {
         nu.with_files(vec![FileWithContent(
             "zip_test.nu",
-            &format!("{}\n", ZIP_POWERED_TEST_ASSERTION_SCRIPT),
+            &format!("{ZIP_POWERED_TEST_ASSERTION_SCRIPT}\n"),
         )]);
 
         let actual = nu!(