[m-rev.] for post-commit review: use semantic help_pieces for diagnostics options

[Julien Fischer]

On Mon, 30 Jun 2025 at 05:52, Zoltan Somogyi <zoltan.somogyi at runbox.com> wrote:

> Convert diagnostics options to semantic help_pieces.
>
> compiler/options.m:
>     As above. In the process, rewrite many options' help texts a bit
>     to use more standard phraseology.
>
>     Fix the category of show_pred_movability.
>
> tests/warnings/help_text.err_exp:
>     Expect the updated help texts.

That looks fine.

Julien.