Merge pull request #80 from erikarn/20230830_ahc_add_logtime_docs

[help] include log_time_format, it's not mentioned in the help file.

lib/tf/tf-help

@@ -2298,6 +2298,9 @@ list commands
   (none)  With no option, lists all open logs.  
   (none)  With an -ligw option, same as "ON".  
 
+  The log_time_format variable controls the time stamp format
+  passed into ftime().
+
   When logging is enabled for a history, lines that are normally recorded in 
   that history are also appended to the log file (unless the line has the "L" 
   nolog attribute).  The previously existing contents of the file, if any, are 
@@ -9238,6 +9241,12 @@ Special global variables
           (flag) Enable automatic login hook.  (See: automatic login, hooks, 
           /world) 
 
+#log_time_format
+#%log_time_format
+  log_time_format=%H:%M:%S
+          Format to pass to ftime() when generating log file entries.
+          (See: ftime, log)
+
 #lp
 #%lp
   lp=off  (flag) Displays partial lines as prompts, after a short timeout.