markdown: Add support for `HTML` table column `align` attribute (#41163)

This PR allows you to define `align="right"` for example to change the
default alignment on **HTML** table columns. This PR also refactors
where we store the alignments in order to make it so you can define it
column based instead of only row based.

See that the `Revenue` column is left aligned instead of the default
`centered`.

**Result**

<img width="1161" height="177" alt="Screenshot 2025-10-25 at 11 01 38"
src="https://github.com/user-attachments/assets/94bda4f0-00c1-4726-a3bd-99b3f2573ef5"
/>


**Code example**

```HTML
<table>
    <tr>
        <th rowspan="2">Region</th>
        <th colspan="2" align="left">Revenue</th>
        <th rowspan="2">Growth</th>
    </tr>
    <tr>
        <th>Q2 2024</th>
        <th>Q3 2024</th>
    </tr>
    <tr>
        <td>North America</td>
        <td>$2.8M</td>
        <td>$2.4B</td>
        <td>+85,614%</td>
    </tr>
    <tr>
        <td>Europe</td>
        <td>$1.2M</td>
        <td>$1.9B</td>
        <td>+158,233%</td>
    </tr>
    <tr>
        <td>Asia-Pacific</td>
        <td>$0.5M</td>
        <td>$1.4B</td>
        <td>+279,900%</td>
    </tr>
</table>
```

Release Notes:

- markdown preview: Add support for `HTML` table column `align`
attribute
79ef10bfc3Remco Smits committed on 10/25/2025, 6:12:05 PM· committed by GitHubparent986ca19
3 files changedLine totals unavailable