musig: remove outdated doc references to ZeroSession error

Author: apoelstra

src/musig.rs

@@ -134,10 +134,6 @@ impl fmt::Display for InvalidTweakErr {
 ///
 /// Remember that nonce reuse will immediately leak the secret key!
 ///
-/// # Errors:
-///
-/// * `ZeroSession`: if the `session_secrand` is supplied is all zeros.
-///
 /// Example:
 ///
 /// ```rust
@@ -517,10 +513,6 @@ impl KeyAggCache {
     /// * `msg`: [`Message`] that will be signed later on.
     /// * `extra_rand`: Additional randomness for mis-use resistance
     ///
-    /// # Errors:
-    ///
-    /// * `ZeroSession`: if the `session_secrand` is supplied is all zeros.
-    ///
     /// Example:
     ///
     /// ```rust