clojuredocs integration inspired on orchard implementation.

Drag clauses forward or backward.

{:a 1, :b 2} -> {:b 2, :a 1}

What constitutes a clause is context dependent. In a map, it will be a
key/value pair. In a vector it will be a single element, unless the vector
establishes bindings as in `let`, in which case it will be a pair of elements.
This code tries to be aware of common functions, data structures and other
forms, and their conventions for establishing clauses.

Though this feature was originally called 'move collection entry', it is now
more generally used to drag any clause forward or backward, even if it isn't
in an immutable collection.