More app-friendly event description (#6684)

* More app-friendly event description

* change origin -> owner

* checked all decl_event! and changed decriptions.

* annotated parameter names for remaining events

Author: warfollowsme

src/lib.rs

@@ -95,11 +95,11 @@ decl_event!(
 		<T as frame_system::Trait>::AccountId,
 		<T as Trait>::AccountIndex
 	{
-		/// A account index was assigned.
+		/// A account index was assigned. [who, index]
 		IndexAssigned(AccountId, AccountIndex),
-		/// A account index has been freed up (unassigned).
+		/// A account index has been freed up (unassigned). [index]
 		IndexFreed(AccountIndex),
-		/// A account index has been frozen to its current account ID.
+		/// A account index has been frozen to its current account ID. [who, index]
 		IndexFrozen(AccountIndex, AccountId),
 	}
 );