TTG: Remove HsUnboundVar, replace with HsHole
This MR addresses #21592 and #25048 (closed) by:
- Removing the import of GHC.Types.Name.Reader in Haskell.Language.Expr in preparation for an independent
haskell-syntaxpackage. This import was used for theRdrNamefield ofHsUnboundVar. - Removing the
HsUnboundVarAST constructor and replacing it withHsHole.
Closes #25048 (closed).
Edited by Adriaan Leijnse