Revert "Don't use raw in comparisons."

This reverts commit 9ff9176.

Per the discussion in #6, having the `Eq` and `Ord` instances ignore the `raw`
field of `Ident` causes more trouble than it's worth, as it causes the parser
to incorrectly deem raw identifiers like `r#return` to be keywords. While we
could fix this issue by changing the parser, this would take quite a bit of
code changes to accomplish. As such, we revert the change here, and we make a
note in the Haddocks for the `Eq` and `Ord` instances to beware of the fact
that `raw` is taken into account.

After this change, the `rustc-tests` test suite passes once more. As such, this
change fixes #6.

Author: RyanGlScott

src/Language/Rust/Data/Ident.hs

@@ -33,13 +33,15 @@ data Ident
   = Ident { hash :: {-# UNPACK #-} !Int  -- ^ hash for quick comparision
           , name :: Name                 -- ^ payload of the identifier
           , raw :: Bool                  -- ^ whether the identifier is raw
-          } deriving (Data, Typeable, Generic, NFData)
-
-instance Eq Ident where
-  x == y = (hash x, name x) == (hash y, name y)
-
-instance Ord Ident where
-  compare x y = compare (hash x, name x) (hash y, name y)
+          }
+  deriving ( Data, Typeable, Generic, NFData
+             -- | Note that this instance takes the 'raw' field into account, so
+             -- the identifiers @x@ and @r#x@ are judged /not/ to be equal.
+           , Eq
+             -- | Note that this instance takes the 'raw' field into account, so
+             -- the identifiers @x@ and @r#x@ are judged /not/ to be equal.
+           , Ord
+           )
 
 -- | Shows the identifier as a string (for use with @-XOverloadedStrings@)
 instance Show Ident where