Improve publisher reliability doc.

Co-authored-by: Luca Cominardi <[email protected]>

zenoh/src/api/builders/publisher.rs

@@ -310,6 +310,8 @@ impl<'a, 'b> PublisherBuilder<'a, 'b> {
     }
 
     /// Change the `reliability`` to apply when routing the data.
+    /// NOTE: Currently `reliability` does not trigger any data retransmission on the wire. 
+    ///             It is rather used as a marker on the wire and it may be used to select the best link available (e.g. TCP for reliable data and UDP for best effort data).
     #[zenoh_macros::unstable]
     #[inline]
     pub fn reliability(self, reliability: Reliability) -> Self {