shorten messages

fih.py

@@ -88,8 +88,11 @@ def mattermost_incident_command( command, args, channel_id, raw_incident_number,
         ev.set_year( datetime.datetime.utcnow().strftime( "%Y" ) )
         written = ev.write()
 
+        short_written = written
+        if len( short_written ) > 512:
+            short_written = short_written[ :509 ] + "..."
         app.mm.posts.create_post( options = { 'channel_id': private_channel_id,
-                                              'message': "#### Written `%s`:\n\n```\n%s```" % ( ev.path_short(), written ),
+                                              'message': "#### Written `%s`:\n\n```\n%s```" % ( ev.path_short(), short_written ),
                                               } )
 
         cmdline = app.config[ "MERCURIAL_BIN" ] + " add " + ev.path_short()