[ja] fix statement about lines output type

[das-g]

In データの読み込み→文字列を扱う after

> open people.txt | lines
───┬──────────────────────────────
 0 │ Octavia | Butler | Writer
 1 │ Bob | Ross | Painter
 2 │ Antonio | Vivaldi | Composer
───┴──────────────────────────────

the prose claims

テーブルにもどってきたので、行を使って作業していることがわかります。

However, lines yields a list, not a table as that sentence might imply. (See PR #764 for a fix of the same problem in English and German.)

[das-g]

Are you sure this has been completed? The concerning line looks unchanged on main: https://github.com/nushell/nushell.github.io/blob/ac3d54d740ab470326388f0fee14d7911d28d0e1/ja/book/loading_data.md?plain=1#L84