Fix outdated rustdoc comment for process_smallbank_playlist
@@ -83,7 +83,7 @@ pub fn generate_smallbank_playlist(
///
/// The playlist input is expected to be the same Yaml format as generated by
/// the `generate_smallbank_playlist` function. All transactions will be
-/// signed with the given `PrivateKey` instance.
+/// signed with the given `Signer` instance.
pub fn process_smallbank_playlist(
output: &mut dyn Write,
playlist_input: &mut dyn Read,
