comment typo fix

src/apis/channels.rs

@@ -22,7 +22,7 @@ pub trait ChannelsAPI {
     /// Get the value of a channel variable
     async fn get_variable(&self, channel_id: &str, var_name: &str) -> Result<String>;
 
-    /// Get the value of a channel variable
+    /// Set the value of a channel variable
     async fn set_variable(&self, channel_id: &str, var_name: &str, var_value: &str) -> Result<()>;
 
     /// Hangs up the channel