Types: Add method ObjectArray.as_generic

AFAIK, it is needed for reverse type lookups.

Author: amotl

src/sqlalchemy_cratedb/type/array.py

@@ -140,5 +140,8 @@ def any(self, other, operator=operators.eq):
     def get_col_spec(self, **kws):
         return "ARRAY(OBJECT)"
 
+    def as_generic(self, **kwargs):
+        return sqltypes.ARRAY
+
 
 ObjectArray = MutableList.as_mutable(_ObjectArray)