[3.6] Fix a typo in Doc/library/functions.rst (GH-1117) (GH-1123)

Replace `For object's ... ` with `For objects ...`
(cherry picked from commit 873ef20d0007b4b120933473e6252d2309a70102)
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 9126535..138f7d0 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -610,7 +610,7 @@
 
   .. note::
 
-    For object's with custom :meth:`__hash__` methods, note that :func:`hash`
+    For objects with custom :meth:`__hash__` methods, note that :func:`hash`
     truncates the return value based on the bit width of the host machine.
     See :meth:`__hash__` for details.