Expand Bolt11InvoiceParameters docs for no-std use

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 61c5958ac6c944957ff5c73849fe7a5e39e80d9d..d4547be8ff6dbdcae872daa96518f78354270ed1 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -9360,7 +9360,8 @@ pub struct Bolt11InvoiceParameters {
        /// [`DEFAULT_EXPIRY_TIME`] by default.
        ///
        /// The creation time used is the duration since the Unix epoch for `std` builds. For non-`std`
-       /// builds, the highest block timestamp seen is used instead.
+       /// builds, the highest block timestamp seen is used instead. In the latter case, use a long
+       /// enough expiry to account for the average block time.
        pub invoice_expiry_delta_secs: Option<u32>,
 
        /// The minimum `cltv_expiry` for the last HTLC in the route. If not set, will use