Update Doc/library/signal.rst

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Author: him2him2

Doc/library/signal.rst

@@ -36,7 +36,7 @@ Execution of Python signal handlers
 A Python signal handler does not get executed inside the low-level (C) signal
 handler.  Instead, the low-level signal handler sets a flag which tells the
 :term:`virtual machine` to execute the corresponding Python signal handler
-at a later point (for example at the next :term:`bytecode` instruction).
+at a later point (for example, at the next :term:`bytecode` instruction).
 This has consequences:
 
 * It makes little sense to catch synchronous errors like :const:`SIGFPE` or