fix: broken link for item valuation updated

Old URL (404 Not Found): https://docs.erpnext.com/docs/v13/user/manual/en/stock/item/item-valuation-fifo-and-moving-average

Updated URL: https://docs.erpnext.com/docs/v13/user/manual/en/stock/articles/calculation-of-valuation-rate-in-fifo-and-moving-average

erpnext/public/js/help_links.js

@@ -671,7 +671,7 @@ frappe.help.help_links["List/Item"] = [
 		label: "Item Valuation",
 		url:
 			docsUrl +
-			"user/manual/en/stock/articles/item-valuation-fifo-and-moving-average",
+			"user/manual/en/stock/articles/calculation-of-valuation-rate-in-fifo-and-moving-average",
 	},
 ];