Add documentation for `Rows` widget

[patriksvensson]

[Elisha-Aguilera]

I can work on this item; will use the Table widget documentation article as a basis. Assuming there's no existing documentation style guides, so I will do my best to mimic the existing documentation.

[patriksvensson]

@Elisha-Aguilera Sounds like a plan! There is, like you say, no style guide, so do what you think is best! 👍

[camelback]

@Elisha-Aguilera Although #1502 addresses the Table documentation is may be reasonable to include it with your PR. I kind of feel like my issue is more related to rows, but applies to the table Widget table.ShowRowSeparators(). I was just going through open issues and came across yours so felt worthwhile to mention.

Of course assuming the issue I raised gets the OK.

Feel free to reference: https://github.com/camelback/spectre.console/commit/6ee8de261edaba473cbabcfa4fa8c4cee300a29c

Cheers!