Remove deprecated --numbered flag from four commands (#7777)

# Description

Remove `--numbered` from ~~`for`~~, `each`, `par-each`, `reduce` and
`each while`. These all provide indexes (numbering) via the optional
second param to their closures.

EDIT: Closes #6986.

# User-Facing Changes

Every command that had `--numbered` listed as "deprecated" in their help
docs is affected.

# 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

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.

---------

Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>

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

@@ -69,23 +69,23 @@ fn sets_the_column_from_a_subexpression() {
 }
 
 #[test]
-fn uses_optional_index_argument_inserting() {
+fn upsert_uses_enumerate_index_inserting() {
     let actual = nu!(
         cwd: ".", pipeline(
-        r#"[[a]; [7] [6]] | upsert b {|el ind| $ind + 1 + $el.a } | to nuon"#
+        r#"[[a]; [7] [6]] | enumerate | upsert b {|el| $el.index + 1 + $el.item.a } | flatten | to nuon"#
     ));
 
-    assert_eq!(actual.out, "[[a, b]; [7, 8], [6, 8]]");
+    assert_eq!(actual.out, "[[index, a, b]; [0, 7, 8], [1, 6, 8]]");
 }
 
 #[test]
-fn uses_optional_index_argument_updating() {
+fn upsert_uses_enumerate_index_updating() {
     let actual = nu!(
         cwd: ".", pipeline(
-        r#"[[a]; [7] [6]] | upsert a {|el ind| $ind + 1 + $el.a } | to nuon"#
+        r#"[[a]; [7] [6]] | enumerate | upsert a {|el| $el.index + 1 + $el.item.a } | flatten | to nuon"#
     ));
 
-    assert_eq!(actual.out, "[[a]; [8], [8]]");
+    assert_eq!(actual.out, "[[index, a]; [0, 8], [1, 8]]");
 }
 
 #[test]