Document init(struct) safety pattern

[anton-trunov]

init does not allow as annotations for its parameters, but sometimes it is really useful and apparently would have saved some debugging time for @Shvandre.

Here is an example of the pattern:
#1023 (comment)

[anton-trunov]

Depends on #1590

[novusnota]

Depends on #1590

Well, the simple workaround is to name the only parameter as params or args. The following snippet works:

import "@stdlib/deploy";

struct Init { foo: Int as uint8 }

contract Quux with Deployable {
    init(args: Init) {
        // ...doing something with args.foo
    }
}

[anton-trunov]

Yeah, it's a workaround for a workaround