bug#66750: Unhelpful text in C-h v for variables with a lambda form as value

[Stefan Monnier]

> How do you feel about this, Stefan (M.)?

Seems like it would leave `lambda` as well as the closure
objects unchanged, so it looks good to me.

The one thing I'd point out is: try to pick a format for the "data in
docstring" that is easily/naturally extensible (contrary to what I did
for the arglists), so that when we get around to adding support for
things like debugging info we could add it there without having to
invent a new format.


        Stefan