Stable API to strip type parameters from type

Is there a function to strip the type parameters from a type? For example:

```
strip_type_parameters(Array{Int,3}) # should return Array
```

There is one way to do this but it is not documented (pointed out by @jakobnissen):

```
strip_type_parameters(T) = Base.typename(T).wrapper
```

Therefore in principle it can change in future versions.

Why not have a stable API for this?