Introduction for using table-reflow.

[Pvanhesteren]

This should resolve #18683 (#18683)

[patrickhlauke]

I'd suggest rewording the first sentence slightly to

Turn traditional tables on their side by using `table-reflow`.

Having thought about it a bit further, I think the impact of people applying this incorrectly is minimal, provided that they do apply it to properly formed data tables (rather than to lay out content, using tables for layout), and only those without any cells spanning multiple rows or columns. So perhaps the last sentence could be removed, and instead add a callout along the lines of

{% callout warning %}
#### Content order and complex tables

Beware that the `table-reflow` style changes the visual order of content. Make sure that you only apply this style to well-formed and simple data tables (and in particular, don't use this for layout tables) with appropriate `<th>` table header cells for each row and column.

In addition, this class will not work correctly for tables with cells that span multiple rows or columns (using `rowspan` or `colspan` attributes).
{% endcallout %}

[Pvanhesteren]

@patrickhlauke, thanks for the quick response. I'll make the changes tomorrow! 👍

[florisverburg]

@patrickhlauke, everything is improved according to your suggestions.

[patrickhlauke]

Lovely. One last request: could you squash this into a single commit?

[florisverburg]

@patrickhlauke, done!

[patrickhlauke]

Perfect, thank you