doc comment for async proc is empty

[enthus1ast]

Example

import asyncdispatch
proc foo*() = 
  ## some foo
  discard

proc baa*(): Future[void] {.async.} =
  ## some baa in async
  discard

proc baz*() = 
  ## some baz
  discard

nim doc file.nim

Current Output

generates a doc without the comments for the async procedure