missing matrix exponentiation methods for `\euler`

Is there any reason for this?  Currently the following is defined in `base/mathconstants.jl`:
```julia
for T in (AbstractIrrational, Rational, Integer, Number, Complex)
    Base.:^(::Irrational{:ℯ}, x::T) = exp(x)
end
```
Is there any reason why this is not simply
```julia
Base.:^(::Irrational{:ℯ}, x) = exp(x)
```