f - fix docs

Author: jkczyz

lightning/src/offers/invoice_request.rs

@@ -1129,7 +1129,7 @@ pub struct InvoiceRequestFields {
 	/// The amount to pay in msats (i.e., the minimum lightning-payable unit for [`chain`]), which
 	/// must be greater than or equal to [`Offer::amount`], converted if necessary.
 	///
-	/// [`chain`]: Self::chain
+	/// [`chain`]: InvoiceRequest::chain
 	pub amount_msats: Option<u64>,
 
 	/// Features pertaining to requesting an invoice.