Mark the `Duration` serialization implementation no-bindings-export

The bindings are being updated to consider all traits even if the
trait itself is no-export, which causes issues generating code
around the `Duration` impl here.

diff --git a/lightning/src/util/ser.rs b/lightning/src/util/ser.rs
index 0e510760e62a3725055cecf3394a17b5b879af9a..919db8f9e57817e1232cfcf7fcf16f7b5d981244 100644 (file)
--- a/lightning/src/util/ser.rs
+++ b/lightning/src/util/ser.rs
@@ -1351,6 +1351,7 @@ impl Readable for Hostname {
        }
 }
 
+/// This is not exported to bindings users as `Duration`s are simply mapped as ints.
 impl Writeable for Duration {
        #[inline]
        fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
@@ -1358,6 +1359,7 @@ impl Writeable for Duration {
                self.subsec_nanos().write(w)
        }
 }
+/// This is not exported to bindings users as `Duration`s are simply mapped as ints.
 impl Readable for Duration {
        #[inline]
        fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {