remove outdated comment

Author: newtonapple

sqlmesh/core/engine_adapter/base.py

@@ -3066,9 +3066,6 @@ def _revoke_grants_config_expr(
     ) -> t.List[exp.Expression]:
         """Returns SQLGlot expressions to revoke grants from a table.
 
-        Note: SQLGlot doesn't yet have a Revoke expression type, so implementations
-        may return other expression types or handle revokes as strings.
-
         Args:
             table: The table/view to revoke permissions from.
             grant_config: Dictionary mapping permissions to lists of grantees.