Align with the Orthogonal Classes framework

[erights]

https://github.com/erights/Orthogonal-Classes

In this syntactic framework, private fields would be declared as

class Foo {
    own #bar = 3, #baz = 4;
    // ...
}

This declares and initializes a public instance fields named "#bar" and "#baz". See https://github.com/erights/Orthogonal-Classes for details and rationale.

attn @allenwb @littledan @zenparsing

[ljharb]

@erights this issue has an example of public fields; did you intend it to be an example of private ones?

[erights]

@ljharb Oops. Copy-edit-paste doesn't work so well when I forget the edit step.