ByteString Ref continued

Attoparsec parser for diff-tree.

Changed fromRef back to producing a String, to avoid needing to convert
every use of it. However, this does mean I'm going to miss some
opportunities where fromRef is used and the result converted back to a
ByteString. Would be worth revisiting that at some point maybe.

Git/LsTree.hs

@@ -96,7 +96,7 @@ parserLsTree = TreeItem
 	<*> A8.takeTill (== ' ')
 	<* A8.char ' '
 	-- sha
-	<*> (Ref . decodeBS' <$> A8.takeTill (== '\t'))
+	<*> (Ref <$> A8.takeTill (== '\t'))
 	<* A8.char '\t'
 	-- file
 	<*> (asTopFilePath . Git.Filename.decode <$> A.takeByteString)
@@ -106,6 +106,6 @@ formatLsTree :: TreeItem -> String
 formatLsTree ti = unwords
 	[ showOct (mode ti) ""
 	, decodeBS (typeobj ti)
-	, decodeBS' (fromRef (sha ti))
+	, fromRef (sha ti)
 	, fromRawFilePath (getTopFilePath (file ti))
 	]