Remove references to line numbers in tutorial text

Removed line numbers in the text because it was difficult to keep these
up-to-date.  Changed some wording and moved sample scripts before (rather
than after) the descriptive text in order to keep it easy to understand.

doc/scripting/framework_logging_factorial_02.bro

@@ -1,8 +1,10 @@
 module Factor;
 
 export {
+    # Append the value LOG to the Log::ID enumerable.
     redef enum Log::ID += { LOG };
 
+    # Define a new type called Factor::Info.
     type Info: record {
         num:           count &log;
         factorial_num: count &log;
@@ -20,6 +22,7 @@ function factorial(n: count): count
 
 event bro_init()
     {
+    # Create the logging stream.
     Log::create_stream(LOG, [$columns=Info]);
     }