taprpc: fix AddInvoice documentation

Author: GeorgeTsagk

taprpc/tapchannelrpc/tapchannel.pb.go

@@ -182,8 +182,8 @@ message AddInvoiceRequest {
     uint64 asset_amount = 2;
 
     // The node identity public key of the peer to ask for a quote for receiving
-    // assets and converting them from satoshis. This must be specified if
-    // there are multiple channels with the given asset ID.
+    // assets and converting them from satoshis. When specified only quotes with
+    // this peer will be negotiated.
     bytes peer_pubkey = 3;
 
     // The full lnd invoice request to send. All fields behave the same way as

taprpc/tapchannelrpc/tapchannel.proto

@@ -1503,7 +1503,7 @@
         "peer_pubkey": {
           "type": "string",
           "format": "byte",
-          "description": "The node identity public key of the peer to ask for a quote for receiving\nassets and converting them from satoshis. This must be specified if\nthere are multiple channels with the given asset ID."
+          "description": "The node identity public key of the peer to ask for a quote for receiving\nassets and converting them from satoshis. When specified only quotes with\nthis peer will be negotiated."
         },
         "invoice_request": {
           "$ref": "#/definitions/lnrpcInvoice",