entc/gen: simplify the way to get gen.Field operation

External templates should not deal with storage configuration

entc/gen/template/dialect/sql/meta.tmpl

@@ -54,7 +54,7 @@ in the LICENSE file in the root directory of this source tree.
 
 	{{ with $.NumM2M }}
 		var (
-			{{- range $_, $e := $.Edges }}
+			{{- range $e := $.Edges }}
 				{{- if $e.M2M }}
 					// {{ $e.PKConstant }} and {{ $e.ColumnConstant }}2 are the table columns denoting the
 					// primary key for the {{ $e.Name }} relation (M2M).

entc/gen/template/dialect/sql/tx.tmpl

@@ -22,9 +22,9 @@ func (c *Client) BeginTx(ctx context.Context, opts *sql.TxOptions) (*Tx, error)
 	cfg.driver = &txDriver{tx: tx, drv: c.driver}
 	return &Tx{
 		config: cfg,
-		{{ range $_, $n := $.Nodes -}}
+		{{- range $n := $.Nodes }}
 			{{ $n.Name }}: New{{ $n.Name }}Client(cfg),
-		{{ end -}}
+		{{- end }}
 	}, nil
 }
 {{ end }}