Derive Macro EnumDocs

#[derive(EnumDocs)]

Returns a const str for the Enum to which it applies.

Example:

#[derive(leftwm_macros::EnumDocs)]
enum LeftWm {
  One,
  /// Doc comment
  Two
}

assert_eq!(LeftWm::documentation(), "\nOne\nTwo\n    Doc comment");

The purpose of this macro is for serializing options of the BaseCommand for leftwm-command