Fixed spacing bugs involving code block attributes.

Closes #763.

src/Text/Pandoc/Readers/RST.hs

@@ -611,7 +611,7 @@ codeblock numberLines lang body =
           kvs     = case numberLines of
                           Just "" -> []
                           Nothing -> []
-                          Just n  -> [("startFrom",n)]
+                          Just n  -> [("startFrom",trim n)]
 
 ---
 --- note block

src/Text/Pandoc/Writers/Markdown.hs

@@ -328,7 +328,7 @@ blockToMarkdown opts (CodeBlock attribs str) = return $
                                             | otherwise -> replicate (n+1) '~'
          backticks = text "```"
          attrs  = if isEnabled Ext_fenced_code_attributes opts
-                     then attrsToMarkdown attribs
+                     then nowrap $ attrsToMarkdown attribs
                      else empty
 blockToMarkdown opts (BlockQuote blocks) = do
   st <- get