More improvements to breakable.

src/Text/Pandoc/Writers/Shared.hs

@@ -548,8 +548,12 @@ breakable t
   | T.any (== ' ') t = mconcat $ foldr go mempty (T.split (==' ') t)
   | otherwise = Text (realLength t) t
  where
-  go "" xs = BreakingSpace : xs
+  go "" xs =
+   case xs of
+     BreakingSpace : _ -> xs
+     _ -> BreakingSpace : xs
   go t' xs = Text (realLength t') t' :
     case xs of
       [] -> xs
+      BreakingSpace : _ -> xs
       _ -> BreakingSpace : xs