Imho it looks strange to have a trailing comma, so I'd rather like to be able to check that no trailing comma is ever used. This could either be done as a property of the ArrayTrailingComma that reverses its meaning or as a separate check that does the reverse.

It could also be considered to make a new check alltogether that also incorporates enums and is just called TrailingComma. It could be configured via tokens on what to apply (enum / array) and via property if commas are enforced or forbidden. Such a check would then deprecate the ArrayTrailingComma check actually.