Implement BoxedRep proposalwip/boxed-rep

This implements the BoxedRep proposal, refactoring the `RuntimeRep`
hierarchy from:

```haskell
data RuntimeRep = LiftedPtrRep | UnliftedPtrRep | ...
```

to

```haskell
data RuntimeRep = BoxedRep Levity | ...
data Levity = Lifted | Unlifted
```

Updates binary, haddock submodules.

Closes #17526.

Metric Increase:
    T12545

1 files changed, 8 insertions, 0 deletions

diff --git a/libraries/template-haskell/Language/Haskell/TH/Syntax.hs b/libraries/template-haskell/Language/Haskell/TH/Syntax.hs
index 6508c07a65..3cb5a44ee8 100644
--- a/libraries/template-haskell/Language/Haskell/TH/Syntax.hs
+++ b/libraries/template-haskell/Language/Haskell/TH/Syntax.hs
@@ -61,6 +61,10 @@ import Foreign.ForeignPtr
 import Foreign.C.String
 import Foreign.C.Types
 
+#if __GLASGOW_HASKELL__ >= 901
+import GHC.Types ( Levity(..) )
+#endif
+
 -----------------------------------------------------
 --
 --              The Quasi class
@@ -816,7 +820,11 @@ class Lift (t :: TYPE r) where
   -- | Turn a value into a Template Haskell expression, suitable for use in
   -- a splice.
   lift :: Quote m => t -> m Exp
+#if __GLASGOW_HASKELL__ >= 901
+  default lift :: (r ~ ('BoxedRep 'Lifted), Quote m) => t -> m Exp
+#else
   default lift :: (r ~ 'LiftedRep, Quote m) => t -> m Exp
+#endif
   lift = unTypeCode . liftTyped
 
   -- | Turn a value into a Template Haskell typed expression, suitable for use