Prefer ErrorCall to ErrorCallWithLocation

This future proofs the code for CLC#285, which will remove
`ErrorCallWithLocation` to de-duplicate duplicate CallStacks.

ErrorCall is already a pattern synonym with the same meaning as it will
have in the future, so this change is backwards compatible too.

Cabal-syntax/src/Distribution/Compat/Binary.hs

@@ -20,4 +20,4 @@ decodeOrFailIO :: Binary a => ByteString -> IO (Either String a)
 decodeOrFailIO bs =
   catch (evaluate (decode bs) >>= return . Right) handler
   where
-    handler (ErrorCallWithLocation str _) = return $ Left str
+    handler (ErrorCall str) = return $ Left str

Cabal-syntax/src/Distribution/Utils/Structured.hs

@@ -277,7 +277,7 @@ structuredDecodeOrFailIO :: (Binary.Binary a, Structured a) => LBS.ByteString ->
 structuredDecodeOrFailIO bs =
   catch (evaluate (structuredDecode bs) >>= return . Right) handler
   where
-    handler (ErrorCallWithLocation str _) = return $ Left str
+    handler (ErrorCall str) = return $ Left str
 
 -- | Lazily reconstruct a value previously written to a file.
 structuredDecodeFileOrFail :: (Binary.Binary a, Structured a) => FilePath -> IO (Either String a)