Remove many GHC dependencies from L.H.S

Continue to prune the `Language.Haskell.Syntax.*` modules out of GHC
imports according to the plan in the linked issue.

Moves more GHC-specific declarations to `GHC.*` and brings more required
GHC-independent declarations to `Language.Haskell.Syntax.*` (extending
e.g. `Language.Haskell.Syntax.Basic`).

Progress towards #21592

Bump haddock submodule for !8308

-------------------------
Metric Decrease:
    hard_hole_fits
-------------------------

1 files changed, 54 insertions, 3 deletions

diff --git a/compiler/Language/Haskell/Syntax/Basic.hs b/compiler/Language/Haskell/Syntax/Basic.hs
index ad3e0e94ba..092231b7d1 100644
--- a/compiler/Language/Haskell/Syntax/Basic.hs
+++ b/compiler/Language/Haskell/Syntax/Basic.hs
@@ -1,12 +1,13 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 module Language.Haskell.Syntax.Basic where
 
-import Data.Int (Int)
-
+import Data.Data
 import Data.Eq
+import Data.Ord
 import Data.Bool
-import Data.Data
+import Data.Int (Int)
 
+import GHC.Data.FastString (FastString)
 
 {-
 ************************************************************************
@@ -42,4 +43,54 @@ type SumWidth = Int
 -- selector
 type ConTag = Int
 
+{-
+************************************************************************
+*                                                                      *
+Field Labels
+*                                                                      *
+************************************************************************
+-}
+
+-- | Field labels are just represented as strings;
+-- they are not necessarily unique (even within a module)
+type FieldLabelString = FastString
+
+
+{-
+************************************************************************
+*                                                                      *
+Field Labels
+*                                                                      *
+************************************************************************
+-}
+
+-- | See Note [Roles] in GHC.Core.Coercion
+--
+-- Order of constructors matters: the Ord instance coincides with the *super*typing
+-- relation on roles.
+data Role = Nominal | Representational | Phantom
+  deriving (Eq, Ord, Data)
+
+{-
+************************************************************************
+*                                                                      *
+Source Strictness and Unpackedness
+*                                                                      *
+************************************************************************
+-}
+
+-- | Source Strictness
+--
+-- What strictness annotation the user wrote
+data SrcStrictness = SrcLazy -- ^ Lazy, ie '~'
+                   | SrcStrict -- ^ Strict, ie '!'
+                   | NoSrcStrict -- ^ no strictness annotation
+     deriving (Eq, Data)
 
+-- | Source Unpackedness
+--
+-- What unpackedness the user requested
+data SrcUnpackedness = SrcUnpack -- ^ {-# UNPACK #-} specified
+                     | SrcNoUnpack -- ^ {-# NOUNPACK #-} specified
+                     | NoSrcUnpack -- ^ no unpack pragma
+     deriving (Eq, Data)