Fix two typos

Doc/lib/libweakref.tex

@@ -32,7 +32,7 @@ exactly like the type of the referent.  The details of these objects
 are likely to change to some degree before the final release as
 experience reports become available.
 
-Please send specific feeback on this module to Fred Drake at
+Please send specific feedback on this module to Fred Drake at
 \email{fdrake@acm.org}.
 
 
@@ -50,7 +50,7 @@ Please send specific feeback on this module to Fred Drake at
   registered callback.
 
   Exceptions raised by the callback will be noted on the standard
-  error output, but cannot be propogated; they are handled in exactly
+  error output, but cannot be propagated; they are handled in exactly
   the same way as exceptions raised from an object's
   \method{__del__()} method.
 \end{funcdesc}