Markdown writer: Fix rendering of tight sublists.

E.g.

    - foo
        - bar
    - baz

Previously a spurious blank line was included before the last item.
Closes #1050.

src/Text/Pandoc/Writers/Markdown.hs

@@ -555,7 +555,14 @@ bulletListItemToMarkdown opts items = do
   contents <- blockListToMarkdown opts items
   let sps = replicate (writerTabStop opts - 2) ' '
   let start = text ('-' : ' ' : sps)
-  return $ hang (writerTabStop opts) start $ contents <> cr
+  -- remove trailing blank line if it is a tight list
+  let contents' = case reverse items of
+                       (BulletList xs:_) | isTightList xs ->
+                            chomp contents <> cr
+                       (OrderedList _ xs:_) | isTightList xs ->
+                            chomp contents <> cr
+                       _ -> contents
+  return $ hang (writerTabStop opts) start $ contents' <> cr
 
 -- | Convert ordered list item (a list of blocks) to markdown.
 orderedListItemToMarkdown :: WriterOptions -- ^ options

tests/Tests/Writers/Markdown.hs

@@ -31,4 +31,8 @@ tests :: [Test]
 tests = [ "indented code after list"
              =: (orderedList [ para "one" <> para "two" ] <> codeBlock "test")
              =?> "1.  one\n\n    two\n\n<!-- -->\n\n    test"
+        , "list with tight sublist"
+             =: bulletList [ plain "foo" <> bulletList [ plain "bar" ],
+                             plain "baz" ]
+             =?> "-   foo\n    -   bar\n-   baz\n"
         ]