Man reader: allow empty simple table cells.

src/Text/Pandoc/Readers/Groff.hs

@@ -356,7 +356,7 @@ tableCell = (enclosedCell <|> simpleCell) >>= lexGroff . T.pack
     manyTill anyChar (try (string "T}"))
   simpleCell = do
     tabChar <- tableTabChar <$> getState
-    many1 (notFollowedBy (char tabChar <|> newline) >> anyChar)
+    many (notFollowedBy (char tabChar <|> newline) >> anyChar)
 
 tableRow :: PandocMonad m => GroffLexer m [GroffTokens]
 tableRow = do

src/Text/Pandoc/Readers/Man.hs

@@ -136,10 +136,12 @@ parseTable = do
   parseTableCell ts = do
     st <- getState
     let ts' = Foldable.toList $ unGroffTokens ts
-    let tcell = do
+    let tcell = try $ do
           skipMany memptyLine
           plain . trimInlines <$> (parseInlines <* eof)
-    res <- lift $ readWithMTokens tcell st ts'
+    res <- if null ts'
+              then return $ Right mempty
+              else lift $ readWithMTokens tcell st ts'
     case res of
       Left e  -> throwError e
       Right x -> return x