doc: Fix small typos in library/multiprocessing (GH-698)

diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 96d1424..6b4a8cb 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -135,7 +135,7 @@
 semaphores created by processes of the program.  When all processes
 have exited the semaphore tracker unlinks any remaining semaphores.
 Usually there should be none, but if a process was killed by a signal
-there may some "leaked" semaphores.  (Unlinking the named semaphores
+there may be some "leaked" semaphores.  (Unlinking the named semaphores
 is a serious matter since the system allows only a limited number, and
 they will not be automatically unlinked until the next reboot.)
 
@@ -179,7 +179,7 @@
 
 Note that objects related to one context may not be compatible with
 processes for a different context.  In particular, locks created using
-the *fork* context cannot be passed to a processes started using the
+the *fork* context cannot be passed to processes started using the
 *spawn* or *forkserver* start methods.
 
 A library which wants to use a particular start method should probably