feat(selling): surface proforma settings in Selling Settings tabs

- Move the Proforma Invoice settings section from the Subcontracting Inward tab
  to the Transaction tab
- List Proforma Invoice in the Document Naming tab so its naming series can be
  configured there

erpnext/selling/doctype/selling_settings/selling_settings.js

@@ -50,6 +50,7 @@ function get_transactions(frm) {
 		{ label: __("Sales Order"), doctype: "Sales Order" },
 		{ label: __("Sales Invoice"), doctype: "Sales Invoice" },
 		{ label: __("Delivery Note"), doctype: "Delivery Note" },
+		{ label: __("Proforma Invoice"), doctype: "Proforma Invoice" },
 	];
 
 	if (frm.doc.cust_master_name !== "Naming Series") {

erpnext/selling/doctype/selling_settings/selling_settings.json

@@ -48,6 +48,9 @@
   "allow_zero_qty_in_sales_order",
   "blanket_orders_section",
   "blanket_order_allowance",
+  "proforma_invoice_section",
+  "enable_proforma_invoice",
+  "default_proforma_print_format",
   "advanced_features_tab",
   "section_break_avhb",
   "enable_tracking_sales_commissions",
@@ -60,9 +63,6 @@
   "allow_delivery_of_overproduced_qty",
   "column_break_mla9",
   "deliver_secondary_items",
-  "proforma_invoice_section",
-  "enable_proforma_invoice",
-  "default_proforma_print_format",
   "default_naming_tab",
   "transaction_naming_html"
  ],