Add broadcastable method for Enum

[AzamatB]

Fixes #30669.

[AzamatB]

Should we consolidate these definitions

broadcastable(x::Union{Symbol,AbstractString,Function,UndefInitializer,Nothing,RoundingMode,Missing,Val}) = Ref(x)
broadcastable(x::Enum) = Ref(x)
broadcastable(x::Ptr) = Ref(x)
broadcastable(r::Regex) = Ref(r)

as one into

broadcastable(x::Union{Symbol,AbstractString,Function,UndefInitializer,Nothing,RoundingMode,Missing,Val,Ptr,Regex,Enum}) = Ref(x)

?

[stevengj]

The Enum definition can't go here, since Enums.jl is loaded after this file. So you need to put Base.broadcastable(x::Enum) = Ref(x) into Enums.jl instead.

We could additionally consolidate this code somewhat as you say, but for simplicity you could leave it as-is in this PR.

[stevengj]

The Fruit enum is already defined in this test file. So you can just do

@test (Vector{Fruit}(undef, 3) .= apple) == [apple, apple, apple]

(Note that there is no need to define the v variable, and the return value of .= is the lhs.)

[AzamatB]

Thanks for the explanations! This is one of my first PRs :)
Superseded by #30675.

[stevengj]

In the future you should update an existing PR rather than creating a new one, so as not to break up the discussion.

[AzamatB]

Thanks for letting me know. I would've done so but was not able to add commits here anymore. I suppose it is because I've made this PR without forking... Maybe it is possible, but I'm not sufficiently good at git to achieve this. I did the new PR properly forking the master.