No we should not support enum types derived from strings

[Walter Bright]

On 5/11/2021 4:00 PM, Andrei Alexandrescu wrote:
> It's unpleasant that `enum : string { f5 = "%d" }` is really the same as `enum 
> f5 = "%d"`. I expected that some anonymous enum type would be generated.

That came about due to the decision to overload enum to create manifest 
constants. This way, a block of manifest constants can be created.