Fix typo in weakref.proxy() documentation.
This closes SF bug #423087.
diff --git a/Doc/lib/libweakref.tex b/Doc/lib/libweakref.tex
index 5e6e819..077e25c 100644
--- a/Doc/lib/libweakref.tex
+++ b/Doc/lib/libweakref.tex
@@ -62,7 +62,7 @@
callable. Proxy objects are not hashable regardless of the
referent; this avoids a number of problems related to their
fundamentally mutable nature, and prevent their use as dictionary
- keys. \var{callable} is the same as the parameter of the same name
+ keys. \var{callback} is the same as the parameter of the same name
to the \function{ref()} function.
\end{funcdesc}