Use ghc-source-gen commit from upstream

The pending PR has been merged to master.

Author: avdv

stackage_snapshot_9.4.6.yaml

@@ -21,8 +21,8 @@ packages:
   commit: 2ab0a8d1ec1f54f3d1a0ecd1a257311389126490
 
 # support GHC 9.4 (see https://github.com/google/ghc-source-gen/pull/102)
-- git: https://github.com/circuithub/ghc-source-gen
-  commit: 7a6aac047b706508e85ba2054b5bedbecfd7eb7a
+- git: https://github.com/google/ghc-source-gen
+  commit: 7527305ed59a47140053cf7bc87432fe1f8804d0
 
 # stackage lts-21.11/ghc 9.4.6 only contain Win32-2.12.0.1
 flags: