Paredit slurp outer form if current form is nested

[PEZ]

When slurping forwardfrom something like this:

(a ((|b)) c)

Then c should be slurped by the form enclosing (b). So should get like so:

(a ((|b) c))

And similarly slurping backwards should slurp a from the enclosing form:

((a (|b)) c)

[PEZ]

Closing this until we know how to properly format things slurped.

[PEZ]

Since we now have a mechanism for formatting arbitrary levels ”up”, maybe it is time to try implement this again.