Fix formatting in messenger.rst for priority section

Author: sfinx13

messenger.rst

@@ -2293,7 +2293,7 @@ Possible options to configure with tags are:
 
 ``priority``
     Defines the order in which the handler is executed when multiple handlers
-    can process the same message; those with higher priority run first, 
+    can process the same message; those with higher priority run first,
     and each handler starts only after the previous one has fully completed.
 
 ``sign``