Fix problems with footnote display on Kindles

1. Amazon "strongly recommends" the use of the `aside` element.
2. Backlinks must be at the start of the footnote or it causes Kindle
   software to mangle the display of footnotes (several footnotes are
   run together, and soft footnote links do not work as pop-overs).

src/Text/Pandoc/Writers/HTML.hs

@@ -479,16 +479,20 @@ footnoteSection opts notes = do
   slideVariant <- gets stSlideVariant
   epubVersion <- gets stEPUBVersion
   let hrtag = if html5 then H5.hr else H.hr
-  let elementType = if html5 then H5.section else H5.div
+  let elementType = if html5 then H5.section else H.div
   let container x
         | slideVariant /= NoSlides = elementType ! A.class_ "footnotes slide" $ x
         | epubVersion == Just EPUB3 = elementType ! A.class_ "footnotes" ! customAttribute "epub:type" "footnotes" $ x
         | otherwise = elementType ! A.class_ "footnotes" $ x
   return $
     if null notes
        then mempty
-       else nl opts >> container (nl opts >> hrtag >> nl opts >>
-              H.ol (mconcat notes >> nl opts) >> nl opts)
+       else
+        nl opts >>
+          container (nl opts >> hrtag >> nl opts >>
+            -- if HTML5 then we're using <aside> and not <li>
+            (if html5 then id else H.ol) (mconcat notes >> nl opts)
+            >> nl opts)
 
 -- | Parse a mailto link; return Just (name, domain) or Nothing.
 parseMailto :: String -> Maybe (String, String)
@@ -1165,20 +1169,19 @@ blockListToNote :: PandocMonad m => WriterOptions -> String -> [Block] -> StateT
 blockListToNote opts ref blocks =
   -- If last block is Para or Plain, include the backlink at the end of
   -- that block. Otherwise, insert a new Plain block with the backlink.
-  let backlink = [Link ("",["footnote-back"],[]) [Str "↩"] ("#" ++ "fnref" ++ ref,[])]
-      blocks'  = if null blocks
-                    then []
-                    else let lastBlock   = last blocks
-                             otherBlocks = init blocks
-                         in  case lastBlock of
-                                  (Para lst)  -> otherBlocks ++
-                                                 [Para (lst ++ backlink)]
-                                  (Plain lst) -> otherBlocks ++
-                                                 [Plain (lst ++ backlink)]
-                                  _           -> otherBlocks ++ [lastBlock,
-                                                 Plain backlink]
+  let backlink = [Link ("",["footnote-back"],[]) [Str (ref ++ ":")] ("#" ++ "fnref" ++ ref,[]), Space]
+      blocks'  = case blocks of
+                  [] -> []
+                  (firstBlock:otherBlocks) ->
+                    case firstBlock of
+                      (Para lst) -> Para (backlink ++ lst) : otherBlocks
+                      (Plain lst) -> Plain (backlink ++ lst) : otherBlocks
+                      _ -> Plain backlink : blocks
+
   in  do contents <- blockListToHtml opts blocks'
-         let noteItem = H.li ! prefixedId opts ("fn" ++ ref) $ contents
+         html5 <- gets stHtml5
+         let noteElement = if html5 then H5.aside else H.li
+         let noteItem = noteElement ! prefixedId opts ("fn" ++ ref) $ contents
          epubVersion <- gets stEPUBVersion
          let noteItem' = case epubVersion of
                               Just EPUB3 -> noteItem ! customAttribute "epub:type" "footnote"