mkdir change flag -s to -v (#7462)

Change in `mkdir` `-s` flag to `-v` to be similar to other commands


# Description

Other commands like `rm`, `mv`, `cp` have a `-v` (`--verbose`) flag.
`mkdir` has a `-s` (`--show-created-paths`), but should be consistent
with other commands.

# User-Facing Changes

- flag `-s` replaced by `-v` in `mkdir` command.


# Tests + Formatting
```
> mkdir -v new_dir
╭───┬───────────────────────────────────╮
│ 0 │ C:\Users\ricardo.monteiro\new_dir │
╰───┴───────────────────────────────────╯
```

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

@@ -63,13 +63,13 @@ fn create_directory_two_parents_up_using_multiple_dots() {
 }
 
 #[test]
-fn show_created_paths() {
+fn print_created_paths() {
     Playground::setup("mkdir_test_2", |dirs, _| {
         let actual = nu!(
          cwd: dirs.test(),
          pipeline(
              r#"
-                 mkdir -s dir_1 dir_2 dir_3
+                 mkdir -v dir_1 dir_2 dir_3
                  | length
              "#
         ));