Support consecutive named Haddock comments

(I don't sufficiently understand the manner in which this arises from a GHC issue, but reliable sources inform me that it does.)

This haddock issue, https://github.com/haskell/haddock/issues/392, apparently is related to the manner in which GHC parses comments.

The way it manifests is that

module Foo
(
  -- $chunk1
  -- $chunk2
  foo,
  -- $chunk3
  bar
)
where

{- $chunk1
This is chunk 1.
-}

{- $chunk2
This is chunk 2.
-}

{- $chunk3
This is chunk 3.
-}

foo = 3
bar = 7

The resulting haddock documentation will include chunks 1 and 3 but not 2.

See the linked ticket for a discussion by Mateusz Kowalczyk explaining how this relates to GHC.

Trac metadata

Trac field	Value
Version	7.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (Parser)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture