`update` and `require` properties for AA

[Vasniktel]

Hello everyone.
I am wondering about `update` and `require` properties of AAs 
which are mentioned to be present here: 
https://dlang.org/spec/hash-map.html#properties
However, this code doesn't compile:
```
import std.stdio;
void main()
{
     class C{}
	int[C] aa;

	auto a = aa.require("a", new C());
}
```
Notice that this is the very code from the specification.
Compiler says: "Error: no property require for type int[C]".
The same situation with `update` property.
So, I'm wondering is this a bug of some kind or just the spec 
isn't updated.

Thank you.