feature request: exporting the restart name

[guicho271828]

Restarts are also the important part of API. please:

@export
(restart-bind ...
   )

@export
(restart-case ...
  (name () ...))

and also the `case,ecase, ccase' keys (less priority):

@export
(case (something)
  (key1 ...)
  (key2 ...))

well, I might have to use a keyword for the restart name.