Make BitFlag values scalars in broadcasting

Duplicates improvement made to Base's Enums: JuliaLang/julia#30675

Author: jmert

src/BitFlags.jl

@@ -25,6 +25,8 @@ Base.isless(x::T, y::T) where {T<:BitFlag} = isless(basetype(T)(x), basetype(T)(
 Base.:|(x::T, y::T) where {T<:BitFlag} = T(Integer(x) | Integer(y))
 Base.:&(x::T, y::T) where {T<:BitFlag} = T(Integer(x) & Integer(y))
 
+Base.broadcastable(x::BitFlag) = Ref(x)
+
 function Base.print(io::IO, x::T) where T<:BitFlag
     compact = get(io, :compact, false)::Bool
     xi = Integer(x)

test/runtests.jl

@@ -66,6 +66,9 @@ end
     # Hashing
     @test Int(flag2a) == Int(flag3a)    # same numerical value, but
     @test hash(flag2a) != hash(flag3a)  # unique hashes as BitFlag
+
+    # Broadcasting
+    @test [flag1a, flag1b] .| flag1c == [flag1a | flag1c, flag1b | flag1c]
 #end
 
 #@testset "Type properties" begin