fix(config, docs) document feedbackPercentage

config.js

@@ -456,6 +456,10 @@ var config = {
     // Enables sending participants' emails (if available) to callstats and other analytics
     // enableEmailInStats: false,
 
+    // Controls the percentage of automatic feedback shown to participants when callstats is enabled.
+    // The default value is 100%. If set to 0, no automatic feedback will be requested
+    // feedbackPercentage: 100,
+
     // Privacy
     //