missing floatmin, floatmax, issubnormal for Quantity

[stevengj]

julia> x = 1.0u"m"
1.0 m

julia> floatmin(x)  # expected result: typeof(x)(floatmin(Float64))
ERROR: MethodError: no method matching floatmin(::Quantity{Float64, 𝐋, Unitful.FreeUnits{(m,), 𝐋, nothing}})

julia> floatmax(x)  # expected result: typeof(x)(floatmax(Float64))
ERROR: MethodError: no method matching floatmax(::Quantity{Float64, 𝐋, Unitful.FreeUnits{(m,), 𝐋, nothing}})

julia> issubnormal(x)  # expected result: false
ERROR: MethodError: no method matching issubnormal(::Quantity{Float64, 𝐋, Unitful.FreeUnits{(m,), 𝐋, nothing}})