implement Reflect for Box<T> where T: Reflect

[jakobhellermann]

TODO: write the PR description

Objective

• it would be nice to be able to reflect types containing Box<T> where T implements reflect

Solution

• TODO: describe why Wrapper is introduced instead of passing everything through the inner value

[Shatur]

@jakobhellermann Looks very useful. What is the state of it? Are you planning to continue working on it?

[jakobhellermann]

@jakobhellermann Looks very useful. What is the state of it? Are you planning to continue working on it?

I think I ran into some problem and didn't continue further at the time, but I don't remember what it was. I'll rebase this over the next week if I have the time and motivation

[richchurcher]

Backlog cleanup: closing due to inactivity, and in favour of #15532. It seems this has had many attempts over the years!