Disallow empty comment

[tqa236]

Look like the intent of the empty comments in some places is to create a visual block of code, but this is done fairly rarely, compared to just use a new line, so I think it's reasonable to enable this rule to avoid code clutter or empty comments as the result of some massy search and replace.

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[mroeschke]

Thanks @tqa236