SA20: Divert CrateCompiler.returning_clause to SA10/SA14 compilers

Apparently, `PGCompiler` does not have a specific implementation for
`returning_clause`, starting with SA20. On the other hand, the generic
implementation changed its method signature, that's why CodeQL would
croak otherwise.

src/crate/client/sqlalchemy/compat/core10.py

@@ -20,6 +20,7 @@
 # software solely pursuant to the terms of the relevant commercial agreement.
 
 import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql.base import PGCompiler
 from sqlalchemy.sql.crud import (REQUIRED, _create_bind_param,
                                  _extend_values_for_multiparams,
                                  _get_multitable_params,
@@ -32,6 +33,12 @@
 
 class CrateCompilerSA10(CrateCompiler):
 
+    def returning_clause(self, stmt, returning_cols):
+        """
+        Generate RETURNING clause, PostgreSQL-compatible.
+        """
+        return PGCompiler.returning_clause(self, stmt, returning_cols)
+
     def visit_update(self, update_stmt, **kw):
         """
         used to compile <sql.expression.Update> expressions

src/crate/client/sqlalchemy/compat/core14.py

@@ -20,6 +20,7 @@
 # software solely pursuant to the terms of the relevant commercial agreement.
 
 import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql.base import PGCompiler
 from sqlalchemy.sql import selectable
 from sqlalchemy.sql.crud import (REQUIRED, _create_bind_param,
                                  _extend_values_for_multiparams,
@@ -33,6 +34,12 @@
 
 class CrateCompilerSA14(CrateCompiler):
 
+    def returning_clause(self, stmt, returning_cols):
+        """
+        Generate RETURNING clause, PostgreSQL-compatible.
+        """
+        return PGCompiler.returning_clause(self, stmt, returning_cols)
+
     def visit_update(self, update_stmt, **kw):
 
         compile_state = update_stmt._compile_state_factory(

src/crate/client/sqlalchemy/compiler.py

@@ -221,12 +221,6 @@ def visit_any(self, element, **kw):
             self.process(element.right, **kw)
         )
 
-    def returning_clause(self, stmt, returning_cols):
-        """
-        Generate RETURNING clause, PostgreSQL-compatible.
-        """
-        return PGCompiler.returning_clause(self, stmt, returning_cols)
-
     def limit_clause(self, select, **kw):
         """
         Generate OFFSET / LIMIT clause, PostgreSQL-compatible.