Inconsistent cell padding in pipe tables

[saf-dmitry]

Issue: In Markdown output format right-aligned cells in pipe tables have no padding on the right side.

Here is a minimal example to reproduce the issue:

After converting file table.text containing a pipe table

| Right | Left | Center | Default |
|--:|:--|:-:|--|
| 12 | 12 | 12 | 12 |
| 123 | 123 | 123 | 123 |
| 1 | 1 | 1 | 1 |

using pandoc v2.9.1.1 with following command

pandoc -t markdown-simple_tables table.text

we get a nicely formatted pipe table, but with right-aligned cells having no padding on the right side:

|  Right| Left | Center | Default |
|------:|:-----|:------:|---------|
|     12| 12   |   12   | 12      |
|    123| 123  |   123  | 123     |
|      1| 1    |    1   | 1       |