Address review comments (add periods in doc)

Author: giampaolo

Doc/whatsnew/3.15.rst

@@ -743,9 +743,9 @@ subprocess
   platform supports it, an efficient event-driven mechanism is used to wait for
   process termination:
 
-  - Linux ≥= 5.3 uses :func:`os.pidfd_open` + :func:`select.poll`
-  - macOS and other BSD variants use :func:`select.kqueue` + ``KQ_FILTER_PROC`` + ``KQ_NOTE_EXIT``
-  - Windows keeps using ``WaitForSingleObject`` (unchanged)
+  - Linux ≥= 5.3 uses :func:`os.pidfd_open` + :func:`select.poll`.
+  - macOS and other BSD variants use :func:`select.kqueue` + ``KQ_FILTER_PROC`` + ``KQ_NOTE_EXIT``.
+  - Windows keeps using ``WaitForSingleObject`` (unchanged).
 
   If none of these mechanisms are available, the function falls back to the
   traditional busy loop (non-blocking call and short sleeps).