Use pipe separator for @-code formatting arguments instead of dash

As reported by Gamgee (PALANT), the MAILW:0 and MAIL:1 lines didn't display
correctly (weren't justified) because of the combination of colons and dash.
Using MAILW#0-L and MAILW#1-L (replacing colons with hash, ugh) would have
also fixed the issue, but the pipe is the newly preferred method of @-code
format arguments, so just do that through-out the file, leaving the colons.
Help save the colons!

text/system.msg

@@ -6,11 +6,11 @@ and has been online continuously for 
y@UPTIME@
w hours.
 
 
ySystem Totals:
w
 
-Users:     
m@TUSER-L.......@
w today: 
m@STATS.NUSERS@
w
-Logons:    
m@STATS.LOGONS-L@
w today: 
m@STATS.LTODAY@
w
-Timeused:  
m@STATS.TIMEON-L@
w today: 
m@STATS.TTODAY@
w
-Messages:  
m@TMSG-L........@
w today: 
m@STATS.PTODAY@
w
-E-mail:    
m@MAILW:0-L.....@
w today: 
m@STATS.ETODAY@
w
-Feedback:  
m@MAILW:1-L.....@
w today: 
m@STATS.FTODAY@
w
-Files:     
m@TFILE-L.......@
w today: 
m@STATS.ULS@
w
+Users:     
m@TUSER|L.......@
w today: 
m@STATS.NUSERS@
w
+Logons:    
m@STATS.LOGONS|L@
w today: 
m@STATS.LTODAY@
w
+Timeused:  
m@STATS.TIMEON|L@
w today: 
m@STATS.TTODAY@
w
+Messages:  
m@TMSG|L........@
w today: 
m@STATS.PTODAY@
w
+E-mail:    
m@MAILW:0|L.....@
w today: 
m@STATS.ETODAY@
w
+Feedback:  
m@MAILW:1|L.....@
w today: 
m@STATS.FTODAY@
w
+Files:     
m@TFILE|L.......@
w today: 
m@STATS.ULS@
w
                  Downloaded today: 
m@STATS.DLS@
w (
m@STATS.DLB@
w 
nbytes
h)